Let mine enemy say - Satan's ordinary method in temptation is to excite strongly to sin, to blind the understanding and inflame the passions; and when he succeeds, he triumphs by insults and reproaches. None so ready then to tell the poor soul how deeply, disgracefully, and ungratefully it has sinned! Reader, take heed.
When I am moved - When moved from my steadfastness and overcome by sin. O what desolation is made by the fall of a righteous soul! Itself covered with darkness and desolation, infidels filled with scoffing, the Church clad in mourning, the Spirit of God grieved, and Jesus crucified afresh, and put to an open shame! O God, save the pious reader from such wreck and ruin!
Lest mine enemy say, I have prevailed against him - I have overpowered him; I have conquered him. That is, to triumph over him as having obtained a complete victory.
And those that trouble me - Hebrew, “My adversaries.” The reference here is the same as in the former member of the verse. It is to the enemies that seemed almost to have triumphed over him already, and under whose power he was ready to sink. “Rejoice.” Exult; triumph.
When I am moved - Moved from my steadfastness or firmness; when I am overcome. Hitherto he had been able to hold out against them; now he began to despair, and to fear that they would accomplish their object by overcoming and subduing him. His ground of apprehension and of appeal was, that by his being vanquished the cause in which he was engaged would suffer, and that the enemies of religion would triumph.