Chapter 19 of my book, “The Catholic Mary”: Quite Contrary to the Bible? (Sep. 2010). I have abridged the many Scripture verses (i.e., merely listed some references rather than present the whole passage) for the sake of brevity.
Some Protestants argue that Catholic terminology and notions regarding petitions or pleas directed towards Mary are unbiblical (and indeed idolatrous), since we invoke her aid and comfort and strength and claim to receive peace by the same means, and (so they claim) such things are only properly referred to as coming from God alone.
Thus, a Catholic who said that Mary gave him strength might have a verse such as the following given to him as a rebuttal (as if it is being violated by so believing):
Psalm 46:1 (RSV, as throughout) God is our refuge and strength, a very present help in trouble.
Or if he said Mary provided spiritual comfort, he might very well be directed to the following verse, as a corrective:
Isaiah 49:13 . . . For the LORD has comforted his people, and will have compassion on his afflicted.
If Mary is said to have granted peace to a troubled soul, the Catholic (or anyone who believes such about Mary and the saints) would be rebuked and “instructed” (with all the very best intentions, I freely grant) with a biblical verse such as:
John 14:27 Peace I leave with you; my peace I give to you; not as the world gives do I give to you. Let not your hearts be troubled, neither let them be afraid.
It is implied (with a fallacious, unbiblical “either/or” reasoning) that only God can be a strength (etc.), and that this somehow precludes human beings participating in the strengthening of other human beings in time of need. The Bible doesn’t teach that. For example, we see the following:
Deuteronomy 3:28 But charge Joshua, and encourage and strengthen him; for he shall go over at the head of this people, and he shall put them in possession of the land which you shall see. [God speaking to Moses]
1 Samuel 23:16 And Jonathan, Saul’s son, rose, and went to David at Horesh, and strengthened his hand in God. (cf. 2 Chron 11:16-17; Ecc 7:19)
Daniel 11:1 And as for me [Daniel], in the first year of Darius the Mede, I stood up to confirm and strengthen him.
Luke 22:32 but I have prayed for you [Peter] that your faith may not fail; and when you have turned again, strengthen your brethren.
Acts 14:22 [Paul and Barnabas] strengthening the souls of the disciples, exhorting them to continue in the faith, and saying that through many tribulations we must enter the kingdom of God.
Acts 15:32 And Judas and Silas, who were themselves prophets, exhorted the brethren with many words and strengthened them.
Acts 15:41 And he [Paul] went through Syria and Cili’cia, strengthening the churches. (cf. Acts 16:5)
Acts 18:23 After spending some time there he [Paul] departed and went from place to place through the region of Galatia and Phryg’ia, strengthening all the disciples.
Romans 1:11 For I [Paul] long to see you, that I may impart to you some spiritual gift to strengthen you,
St. Paul in turn gives God the ultimate credit as the original source of all such strength, channeled through himself and other spiritual leaders (“both / and” reasoning again: Rom 16:15; Eph 3:16; 6:10; Phil 4:13; Col 1:11; 2 Thess 3:3; 1 Tim 1:12; 2 Tim 2:1; 4:17). St. Peter does the same (1 Pet 4:11; 5:10).
At least one passage even illustrates how God uses things in His creation to strengthen man:
Psalm 104:13-15 From thy lofty abode thou waterest the mountains; the earth is satisfied with the fruit of thy work.  Thou dost cause the grass to grow for the cattle, and plants for man to cultivate, that he may bring forth food from the earth,  and wine to gladden the heart of man, oil to make his face shine, and bread to strengthen man’s heart.
Note how “heart” is used here instead of body. This refers to the spirit, not merely physical energy from nutrition. Other similar biblical concepts concerning aid from others (not solely God to the exclusion of men) abound:
Encouragement (Deut 1:38; 2 Chron 35:2; Acts 18:27; 20:2; 27:36; Rom 1:12; 1 Cor 14:3, 31; Eph 6:22; Col 2:2; 4:8; 1 Thess 2:11;5:11, 14).
Exhortation (Lk 3:18; Acts 2:40; 11:23; 14:22; 15:31-32; 16:40; 20:1; Rom 12:8; 1 Thess 2:11; 3:2; 4:1, 10; 5:14; 2 Thess 3:12; 1 Tim 5:1; 2 Tim 4:2; Titus 2:15; Heb 3:13; 13:22; 1 Pet 5:1, 12)
Help (Gen 2:18, 20; Is 41:6 [cf. 10, 13-14]; Acts 16:9; 18:27; 20:35; Rom 16:2; 1 Cor 12:28; 2 Cor 1:11; 1 Thess 5:14).
Comfort (of the spiritual sort) is also referred to as coming from fellow human beings: not just from God:
Job 42:11 Then came to him all his brothers and sisters and all who had known him before, and ate bread with him in his house; and they showed him sympathy and comforted him for all the evil that the LORD had brought upon him; and each of them gave him a piece of money and a ring of gold. (cf. 1 Chr 7:22)
2 Corinthians 1:4, 6-7 who comforts us in all our affliction, so that we may be able to comfort those who are in any affliction, with the comfort with which we ourselves are comforted by God. . . .  If we are afflicted, it is for your comfort and salvation; and if we are comforted, it is for your comfort, which you experience when you patiently endure the same sufferings that we suffer.  Our hope for you is unshaken; for we know that as you share in our sufferings, you will also share in our comfort.
2 Corinthians 2:7 so you should rather turn to forgive and comfort him, or he may be overwhelmed by excessive sorrow.
2 Corinthians 7:7 and not only by his coming but also by the comfort with which he was comforted in you, as he told us of your longing, your mourning, your zeal for me, so that I rejoiced still more. (cf. 7:4, 6, 13)
1 Thessalonians 3:7 for this reason, brethren, in all our distress and affliction we have been comforted about you through your faith;
1 Thessalonians 4:18 Therefore comfort one another with these words. (cf. Col 4:11; Philemon 1:7)
God even compares His comfort with human (and animal) maternal comfort and care:
Isaiah 66:13 As one whom his mother comforts, so I will comfort you; you shall be comforted in Jerusalem.
Matthew 23:37 O Jerusalem, Jerusalem, killing the prophets and stoning those who are sent to you! How often would I have gathered your children together as a hen gathers her brood under her wings, and you would not!
Lastly, human beings extend to each other God’s peace — as well as grace and mercy (God is not the only One who does this, though He is the ultimate origin and cause of it):
1 Samuel 25:6 And thus you shall salute him: “Peace be to you, and peace be to your house, and peace be to all that you have.” (cf. 1:17; 25:35; Jud 18:6)
Matthew 10:13 And if the house is worthy, let your peace come upon it; but if it is not worthy, let your peace return to you. (cf. 5:9; Lk 10:5-6)
Romans 1:7 To all God’s beloved in Rome, who are called to be saints: Grace to you and peace from God our Father and the Lord Jesus Christ.
1 Corinthians 1:3 Grace to you and peace from God our Father and the Lord Jesus Christ. (cf. 2 Cor 1:2; Gal 1:3; 6:16; Eph 1:2; 6:23; Phil 1:2; Col 1:2; 1 Thess 1:1; 2 Thess 1:2; 1 Tim 1:2; 2 Tim 1:2; Titus 1:4; Philem 1:3)
1 Peter 5:14 . . . Peace to all of you that are in Christ.
2 Peter 1:2 May grace and peace be multiplied to you in the knowledge of God and of Jesus our Lord. (cf. 1 Pet 1:2)
3 John 1:15 Peace be to you. . . .
Jude 1:2 May mercy, peace, and love be multiplied to you.
St. Paul, for example, also asks God to give others peace (an example of God using men as instruments to spread His blessings):
2 Thessalonians 3:16 Now may the Lord of peace himself give you peace at all times in all ways. The Lord be with you all.
Now, Mary and other saints are still very much alive; they are not unconscious or nonexistent. Jesus rebuked the Sadducees, who denied the resurrection and afterlife:
Mark 12:26-27 “And as for the dead being raised, have you not read in the book of Moses, in the passage about the bush, how God said to him, ‘I am the God of Abraham, and the God of Isaac, and the God of Jacob’?  He is not God of the dead, but of the living; you are quite wrong.”
Luke 20:34-38 And Jesus said to them, “The sons of this age marry and are given in marriage;  but those who are accounted worthy to attain to that age and to the resurrection from the dead neither marry nor are given in marriage,  for they cannot die any more, because they are equal to angels and are sons of God, being sons of the resurrection.  But that the dead are raised, even Moses showed, in the passage about the bush, where he calls the Lord the God of Abraham and the God of Isaac and the God of Jacob.  Now he is not God of the dead, but of the living; for all live to him.” (cf. Mt 22:29-32)
If one denies this, serious problems with biblical revelation arise (not at all tied only to distinctively Catholic theology, but to all trinitarian Christian theology). Therefore, Mary and other departed saints can extend to us these blessings and graces, such as peace, comfort, encouragement, help, exhortation, and strength, just as believers extend these things to each other on earth.
Death does not end participation in the Body of Christ. To the contrary, it magnifies it and makes it more powerful. And Mary, as the Mother of God the Son, has more power than any other creature to pray and comfort those of us on earth who ask for her aid. This is according to explicit biblical principles as well:
James 5:13-18 Is any one among you suffering? Let him pray. Is any cheerful? Let him sing praise.  Is any among you sick? Let him call for the elders of the church, and let them pray over him, anointing him with oil in the name of the Lord;  and the prayer of faith will save the sick man, and the Lord will raise him up; and if he has committed sins, he will be forgiven.  Therefore confess your sins to one another, and pray for one another, that you may be healed. The prayer of a righteous man has great power in its effects.  Eli’jah was a man of like nature with ourselves and he prayed fervently that it might not rain, and for three years and six months it did not rain on the earth.  Then he prayed again and the heaven gave rain, and the earth brought forth its fruit.
It is precisely because Mary is Jesus’ mother (and given extraordinary graces for that purpose) that her intercession is so powerful: more so than any other creature’s.
Catholics do not believe (as we are often falsely accused) that Mary is the source of salvation; only that she is a vessel of God’s grace and salvation, which is nothing more than what Paul says about himself and indeed about all believers (see, e.g., 2 Cor 4:8-15; Eph 3:2; 4:29; Phil 1:7, 19; cf. 1 Pet 4:10; longer list in chapter 18).
Every time we pray for someone else we are a vessel of grace. Protestants too often confuse intercession and Mary’s maternal role as mother of believers (hence Jesus called Mary John’s mother from the cross), with some supposed identification of Mary in Catholicism as the source and origin of salvation. Only God is that: and this is what we teach.
No one (i.e., who correctly understands orthodox Catholicism) is worshiping Mary. Seeking comfort from her is completely different from worship. All of Mary’s power to help us is directly derived from God: solely by His grace. Properly understood, such aid from Mary is never intended in Catholic theology to usurp or compete with God’s grace and power: she is merely His vessel or channel.
Mary Mediatrix & the Bible (vs. Dr. Robert Bowman) [8-1-03]
Biblical Evidence for Mary Mediatrix [11-25-08]
Why Pray to Saints Rather than God? [9-4-15]
Dialogue on Praying to Abraham (Luke 16) [5-22-16]
Invocation & Intercession of Saints & Angels: Bible Proof [10-22-16 and 1-9-17]
Dialogue: Rich Man’s Prayer to Abraham (Luke 16) and the Invocation of Saints (vs. Lutheran Pastor Ken Howes) [5-3-17]