Charles H. Spurgeon on Psalms 119:108

Accept...the freewill offerings of my mouth, O Lord, and teach me thy judgments. Two things we are here taught to pray for in reference to our religious performances.

1. Acceptance of them: this we must aim at in all we do in religion, that whether present or absent we may be accepted of the Lord. That which David here earnestly prays for the acceptance of is "the freewill offerings, "not of his purse, but of his "mouth, "his prayers and praises; "the calves of our lips" (Hosea 14:2); "the fruit of our lips" (Hebrews 13:15); these are the spiritual offerings which all Christians, as spiritual priests, must offer to God; and they must be "freewill offerings; "for we must offer them abundantly and cheerfully; and it is this willing mind that is accepted. The more there is of freeness and willingness in the service of God, the more pleasing it is to him.

2. Assistance in them: "Teach me thy judgments." We cannot offer any thing to God which we have reason to think he will accept of, but what he is pleased to instruct us in the doing of; and we must be as earnest for the grace of God in us as for the favour of God toward us. Matthew Henry.