Charles H. Spurgeon on Psalms 106:12

Then believed they his words. There is a temporary faith, as Mark calls it in (Mr 4:17), which is not so much a fruit of the Spirit of regeneration, as of a certain mutable affection, and so it soon passeth away. It is not a voluntary faith which is here extolled by the prophet, but rather that which is the result of compulsion, namely, because men, whether they will or not, by a sense which they have of the power of God, are constrained to show some reverence for him. This passage ought to be well considered, that men, when once they have yielded submission to God, may not deceive themselves, but may know that the touchstone of faith is when they spontaneously receive the word of God, and constantly continue firm in their obedience to it. John Calvin.