John Calvin Commentary Psalms 102:8

"Mine enemies reproach me all the day; They that are mad against me do curse by me." — Psalms 102:8 (ASV)

My enemies have reviled me daily. The faithful, to stir God's compassion towards them, tell Him that they are not only objects of mockery to their enemies, but also that their enemies swore by them. The indignity complained of is that the ungodly so shamefully triumphed over God’s chosen people as even to borrow from their calamities a form of swearing and imprecation. This was to regard the fate of the Jews as a notable example when uttering curses.

Therefore, when today the ungodly similarly give themselves free rein in pouring out abusive language against us, let us learn to fortify ourselves with this armor, by which such temptation, however sharp, may be overcome. The Holy Spirit, in giving the faithful this form of prayer, intended to testify that God is moved by such revilings to help His people, even as we find it stated in Isaiah 37:23:

Whom have you reproached and blasphemed, and against whom have you exalted your voice? Even against the Holy One of Israel;

And in the verse immediately preceding, the prophet had said, He has despised you, O daughter of Zion! Against you he has shaken his head, O daughter of Jerusalem! It is surely an inestimable comfort that the more insolent our enemies are against us, the more God is incited to gird Himself to aid us.

In the second clause, the inspired writer expresses more strongly the cruelty of his enemies when he speaks of their being mad against him. As the verb הלל, halal, which we have rendered mad, generally signifies to praise, it might here be understood as having, by the figure antiphrasis, a sense the very opposite—those who dispraised or reproached me. But it is better to follow the commonly received interpretation.

Some maintain that they are called mad, because they manifested their own folly, making it evident from the way they acted that they were worthless persons; but this opinion does too much violence to the text. The more satisfactory sense is that the people of God charge revilers with cruelty or furious hatred.