Charles H. Spurgeon on Psalms 125:4

Do good, O LORD, unto those that be good, and to them that are upright in their hearts. Men to be good at all must be good at heart. Those who trust in the Lord are good; for faith is the root of righteousness, and the evidence of uprightness. Faith in God is a good and upright thing, and its influence makes the rest of the man good and upright. To such God will do good: the prayer of the text is but another form of promise, for that which the Lord prompts us to ask he virtually promises to give. Jehovah will take off evil from his people, and in the place thereof will enrich them with all manner of good. When the rod of the wicked is gone his own rod and staff shall comfort us. Meanwhile it is for us to pray that it may be well with all the upright who are now among men. God bless them, and do them good in every possible form. We wish well to those who do well. We are so plagued by the crooked that we would pour benedictions upon the upright.