31 The law of his God is in his heart; none of his steps  shall slide.
31 The law of their God is in their hearts; their feet do not slip.
31 The law of his God is in his heart; his steps do not slip.
31 His heart pumps God's Word like blood through his veins; his feet are as sure as a cat's.
31 The law of his God is in his heart; None of his steps shall slide.
31 They have made God's law their own, so they will never slip from his path.
Matthew Henry's Commentary on Psalm 37:31
Commentary on Psalm 37:21-33
(Read Psalm 37:21-33)
The Lord our God requires that we do justly, and render to all their due. It is a great sin for those that are able, to deny the payment of just debts; it is a great misery not to be able to pay them. He that is truly merciful, will be ever merciful. We must leave our sins; learn to do well, and cleave to it. This is true religion. The blessing of God is the spring, sweetness, and security of all earthly enjoyments. And if we are sure of this, we are sure not to want any thing good for us in this world. By his grace and Holy Spirit, he directs the thoughts, affections, and designs of good men. By his providence he overrules events, so as to make their way plain. He does not always show them his way for a distance, but leads them step by step, as children are led. God will keep them from being ruined by their falls, either into sin or into trouble, though such as fall into sin will be sorely hurt. Few, if any, have known the consistent believer, or his children, reduced to abject, friendless want. God forsakes not his saints in affliction; and in heaven only the righteous shall dwell for ever; that will be their everlasting habitation. A good man may fall into the hands of a messenger of Satan, and be sorely buffeted, but God will not leave him in his enemy's hands.