"It is good for me that I was afflicted, that I might learn your statutes" (Ps. 119:71).
Why is it that something which would be absent in future glory be deemed by the Psalmist as something good?
Because suffering brings us back to God. It is reality on a megaphone blaring in our ears, "Creature!" It puts us in our rightful place—close to God, in a relationship of humble and grateful dependence on Him for everything pertaining to our well-being: "The Lord is near to the brokenhearted and saves the crushed in spirit" (Ps. 34:18).
Calvin, commenting on Ps. 119:71 says:
"He here confirms the sentiment which we have previously considered — that it was profitable to him to be subdued by God’s chastisements, that he might more and more be brought back and softened to obedience. By these words he confesses that he was not exempt from the perverse obstinacy with which all mankind are infected; for, had it been otherwise with him, the profit of which he speaks, when he says that his docility was owing to his being brought low, would have been merely pretended; even as none of us willingly submits his neck to God, until He soften our natural hardness by the strokes of a hammer. It is good for us to taste continually the fruit which comes to us from God’s corrections, that they may become sweet to us; and that, in this way, we, who are so rebellious and wayward, may suffer ourselves to be brought into subjection."
And on Ps. 34:18 he says:
"David here exemplifies and extends still more the preceding doctrine, that God is the deliverer of his people, even when they are brought very low, and when they are, as it were, half-dead. It is a very severe trial, when the grace of God is delayed, and all experience of it so far withdrawn, as that our spirits begin to fail; nay more, to say that God is nigh to the faithful, even when their hearts faint and fall them, and they are ready to die, is altogether incredible to human sense and reason. But by this means his power shines forth more clearly, when he raises us up again from the grave. Moreover, it is meet that the faithful should be thus utterly cast down and afflicted, that they may breathe again in God alone. From this we also learn, that nothing is more opposed to true patience than the loftiness of heart of which the Stoics boast; for we are not accounted truly humbled until true affliction of heart has abased us before God, so that, having prostrated ourselves in the dust before him, he may raise us up. It is a doctrine full of the sweetest consolation, that God departs not from us, even when we are overwhelmed by a succession of miseries, and, as it were, almost deprived of life."