It isn't unusual for us to judge who we are and how we have lived our lives in relation to what others have done. For example, parents may feel that they are unsuccessful because their children have failed in some important way. But if that were the measure of success, then God himself would be a failure. Few of his children, in fact none of them on their own, measure up to his expectations. That is why he sent his Son.
So we ought to cease judging, not only others but also ourselves. Jesus has commanded us to do so.
What Jesus means in the commandment not to judge is more clear in Luke than in Matthew: "Judge not and you will not be judged; condemn not and you will not be condemned; free others from your demands and you will be freed" (Lk. 6:37; my translation).
If I judge myself to be a failure as a parent because of what my children have done, or if I judge myself to have succeeded because of what they have done, I am not yet merciful (compassionate) as my Father in heaven is merciful (Lk. 6:36). So we are not to condemn others. We are not to act as if we can decide their worth or fate. And that applies equally well to ourselves. We should leave judgment to God.
But the refusal to judge ought to go beyond refraining from doing. It means more than finding an opportunity to condemn self or other but holding oneself back from doing so. It ought also to mean not seeing the world in terms of judgment at all.
If I refrain from judgment, I have already implicitly judged: this person is worthy of my judgment, but I won't do it. Better would be not to see the person as worthy of judgment in the first place. Refraining from sin is good, but it is better not to have seen the world as inviting one to sin.
That seems like an impossible demand, seeing the world as God sees it rather than as a fallen human being does. A revelation received through Joseph Smith in 1829 tells us what it requires:
O ye that embark in the service of God, see that ye serve him with all your heart, might, mind and strength, that ye may stand blameless before God at the last day . . . . And faith, hope, charity and love, with an eye single to the glory of God, qualify him for the work. (D&C 4:2-5; emphasis added)
We can judge only because our eye is on something other than the glory of God, which LDS scripture defines as his work (Moses 1:39). We are qualified for God's work when that is what we have our eye on. And if we have our eye on that work, the work of bringing human beings back to the Father, then we will not see anyone, whether another or ourselves, as an object of possible judgment. We will see as God sees.
That doesn't mean that Christians are simply blind to things that go wrong or to evil. Paul says, "The spiritual person carefully examines everything" (1 Cor. 2:15; my translation).
Those reborn in Christ see the world differently. They can evaluate, and they do so honestly and accurately. In their careful examination of self and others, they may see that this or that did not work, that doing a particular thing was not just mistaken but wrong, that they have cause for repentance. But even in making those accurate assessments, they do not condemn; they see as a loving Parent sees.
When our children or friends or leaders abandon us psychologically or spiritually, taking paths that we know will bring them and perhaps others hurt and pain, we ache for them. Like the father with two sons who went astray, each in his own way (Lk. 15:11-32), we know they are wayward. But we wait, ready to welcome them home with kisses and a feast when we see them coming while "yet a great way off" (Lk. 15:20).
And while we wait for them to return, our eye remains not on ourselves, whether on our successes or our failures, but on the work of the Father, including work for those who have strayed.
Another of Joseph Smith's revelations promises great things if our eye remains on that work, the work of divine love:
Let thy bowels also be full of charity towards all men, and to the household of faith, and let virtue [moral excellence] garnish [clothe, supply a means of defense for] thy thoughts unceasingly; then shall thy confidence wax strong in the presence of God; and the doctrine of the priesthood shall distill upon thy soul as the dews from heaven.The Holy Ghost shall be thy constant companion, and thy scepter an unchanging scepter of righteousness and truth; and thy dominion shall be an everlasting dominion, and without compulsory means it shall flow unto thee forever and ever.
If we live the divine life made possible through genuine conversion, a life of godly charity, then without need to judge others or ourselves, living in a world in which judgment doesn't arise as a possibility and good comes without force, we will be confident in God's presence and will receive his everlasting kingdom as our own (cf. Rom. 8:16-17).