Adam Clarke on Psalms 107:42

The righteous shall see it - The wicked are as inconsiderate as they are obstinate and headstrong.

And rejoice - To have such ample proofs that God ruleth in the earth, and that none that trust in him shall be desolate.

All iniquity shall stop her mouth - God's judgments and mercies are so evident, and so distinctly marked, that atheism, infidelity, and irreligion are confounded, and the cause of error and falsehood has become hopeless. It was only the mouth that could do any thing; and that only by lies, calumnies, and blasphemies: but God closes this mouth, pours contempt upon the head and judgment upon the heart. This may also be applied to the case of the Israelttes and the Babylonians. The former, when they turned to God, became righteous; the latter were a personification of all iniquity.