Evangelicals commonly say things like, God would have been perfectly just if He had sent the whole of sinful humanity to hell.
Anselm would beg to differ.
God created “rational beings” so that “through rejoicing in him, it might be blessedly happy” (Cur Deus Homo, 315). Man was created for happiness.
If man had not sinned, he would not have died, and so would have obtained happiness: “it is repugnant to the wisdom and justice of God that he should force [man], if guiltless, to suffer death.” And this is “proof” of the necessity of resurrection: “if man is to be restored in perfection, he ought to be reconstituted as the sort of being he would have been if he had not sinned” (316). That is, God’s design for humanity (happiness) requires resurrection, if man is to be restored.
But must he be restored to perfection? Anselm presents the alternatives: “either God will complete what he has begun, or it was to no available that he created this life-form [natura] – so sublime a life-form, and with such great good as its purpose” (317). God began by creating rational beings for happiness. As Anselm sees it, if man doesn’t attain happiness, then God has failed to achieve what He set out to achieve.
God’s purpose cannot be so thwarted: “if it is recognized that God has made nothing more precious than rational nature, whose intended purpose is that it should rejoice in him, it is totally foreign to him to allow any rational type of creature to perish utterly. . . . It is necessary, therefore, that, with regard to the nature of mankind, God should finish what he has begun” (317).
Boso asks the obvious question: Doesn’t this reduce the gratuity of grace: “how is it that we are to attribute our salvation to his grace, if it is of necessity that he saves us?” (318).
Anselm distinguishes: “There is a necessity which removes graciousness from someone who is acting beneficently, or diminishes it, and there is a necessity whereby the debt of gratitude is owed for a benefaction is increased” (318). If someone is forced to do good by circumstances, his good is not praiseworthy. But when someone “subjects himself freely to a force which inevitably requires him to do good, and is not reluctant to endure it, then he certainly deserves greater gratitude for his good deed” (318). This is “an act of grace, because it is under no one’s compulsion that he undertakes it and carries it out, but freely.” Making a promise to do something puts you under an obligation; it is “necessary” to keep the promise if you don’t want to be considered, and to be, a liar.
The “necessity” of God saving sinful humanity is of the latter sort. God knew what Adam would do before he created him, and yet “by his own goodness in creating him, he put himself under an obligation to bring his good beginning to fulfillment” (319). In an ultimate sense, God does nothing by necessity, since he cannot be forced to do anything. Anselm says that the necessity consists only in “the unchangeability of God’s honor.”
God must, if He is a just and good God, redeem humanity. The necessity isn’t imposed from outside; it is a “necessity” of God’s own character, God being God. Yet it is a kind of necessity, and Anselm rejects the notion that God could be the good and just God He is if He had condemned all humanity to hell.