John Calvin Commentary Psalms 51:13

"Then will I teach transgressors thy ways; And sinners shall be converted unto thee." — Psalms 51:13 (ASV)

I will teach transgressors thy ways. Here he speaks of the gratitude that he would feel if God answered his prayer, and commits to showing it by exerting himself to bring about the conversion of others by his example.

Those who have been mercifully recovered from their falls will feel fervently moved by the common principle of charity to extend a helping hand to their brethren. In general, those who share in God's grace are constrained by religious principle and by regard for God's glory, to desire that others should also be brought to share in it.

The optimistic manner in which he expresses his expectation of converting others is not unworthy of our notice. We are too apt to conclude that our attempts at reclaiming the ungodly are vain and ineffectual, and to forget that God is able to crown them with success.