Charles H. Spurgeon on Psalms 119:124

Deal with thy servant according unto thy mercy. Here he recollects himself: although before men he was so clear that he could challenge the word of righteousness, yet before the Lord, as his servant, he felt that he must appeal to mercy. We feel safest here. Our heart has more rest in the cry, "God be merciful to me, "than in appealing to justice. It is well to be able to say, "I have done judgment and justice, "and then to add in all lowliness, yet "deal with thy servant according unto thy mercy." The title of servant covers a plea; a master should clear the character of his servant if he be falsely accused, and rescue him from those who would oppress him; and, moreover, the master should show mercy to a servant? even if he deal severely with a stranger. The Lord condescendingly deals, or has communications with his servants, not spurning them, but communing with them; and this he does in a tender and merciful way, for in any other form of dealing we should be crushed into the dust. "And teach me thy statutes." This will be one way of dealing with us in mercy. We may expect a master to teach his own servant the meaning of his own orders. Yet since our ignorance arises from our own sinful stupidity, it is great mercy on God's part that he condescends to instruct us in his commands. For our ruler to become our teacher is an act of great grace, for which we cannot be too grateful. Among our mercies this is one of the choicest.