20. Our soul waiteth upon Jehovah. What the Psalmist has hitherto spoken concerning God’s providence, and particularly concerning that faithful guardianship by which he protects his people, he has spoken not so much from himself as from the mouth of the Holy Spirit. He now, therefore, in the name of the whole Church, raises his song to declare that there is nothing better than to commit our welfare to God. Thus we see that the fruit of the preceding doctrine is set forth to all true believers, that they may unhesitatingly cast themselves with confidence, and with a cheerful heart, upon the paternal care of God. In this matter, the Psalmist declares nothing concerning himself in particular, but unites the whole of the godly with him in the acknowledgement of the same faith. There is an emphasis in the word soul which should be attended to; for, although this is a common mode of speech among the Hebrews, yet it expresses earnest affection; as if believers should say, We sincerely rely upon God with our whole heart, accounting him our shield and help.

21. Surely our heart shall rejoice in him. As the particle כי, ki, which is twice employed in this verse, has various meanings in Hebrew, it may be understood in a twofold sense here. If we expound it affirmatively in both clauses, the sense will be, that believers glory both in their joy and in their hope. Nor do I think it improper that these two should be referred to distinctly in the same context thus: Surely God shall always be our joy; surely his holy name shall be like an impregnable fortress for our refuge. Whence is it that believers continue perseveringly to call upon God, but because, satisfied with his favor, they have always, amidst their sorrows and griefs, this comfort, which is sufficient to maintain their cheerfulness? Justly, therefore, do believers affirm, in the first place, that their heart rejoices in the Lord; because, freed from wandering after the fascinations of the world, they neither waver nor hesitate at every change of fortune, but place the whole felicity of their life in enjoying the free and paternal favor of God. They afterwards add, in the second place, that they trust in his holy name. If any one, however, choose to understand the particle כי, ki, as meaning because, assigning a cause or reason, the sense will be no less properly and elegantly expressed in this way: Because our hope is fixed on God, he will be equally ready on his part to minister to us continual matter of joy. And experience undoubtedly proves, that when men are overwhelmed with sorrow, and pine away with care, grief, and anxiety, it is that they may receive the recompense of their folly; seeing that there is nothing to which they are led with more difficulty, than to set their hopes on God alone, and not to exult in their own deceitful imaginations, with which they please themselves.

22. Let thy mercy be on us, O Jehovah! At length the psalm concludes with a prayer, which the sacred writer offers in the name of all the godly, that God would make them feel from the effect that they have not relied on the divine goodness in vain. In the meantime, the Spirit, by dictating to us this rule of prayer by the mouth of the prophet, teaches us, that the gate of divine grace is opened for us when salvation is neither sought nor hoped for from any other quarter. This passage gives us another very sweet consolation, namely, that if our hope faint not in the midst of our course, we have no reason to fear that God will fail to continue his mercy towards us, without intermission, to the end of it.