There is a great principle involved in these words. When once a person or possession had been solemnly dedicated to God, it was not permissible to withdraw from the obligations which had been assumed. Once given, the offering was regarded as God's property, and might not be resumed by the offerer, or placed to any inferior use.
This regulation is specially applicable to our conception and practice of consecration. We are Christ's; by the gift of the Father, by the purchase of the blood of Christ, by the sealing of the Spirit; but a moment often comes in the life of the earnest believer when the Lord appears to claim a more earnest recognition of His rightful claim. Then thoughtfully and earnestly, spirit, soul, and body, are laid upon the altar, and we solemnly declare, "I am Thine, O Lord!"
When once this is done, we must reckon that God has accepted us, and that we cannot repeat the gift. We may perpetually refer to it, and acknowledge its abiding obligation, and apply its principle to all those new departments and functions which are perpetually increasing on us; but we can no more repeat it, than could the Israelite give God the firstling lamb, since it was already His (Lev 27:26).
If we go back from the attitude we have once taken up, we must confess our relapse with tears and deep contrition, asking to be restored, waiting to be put back again into the old place by our merciful and compassionate High Priest. We cannot undo that past; but we may ask Him to restore us to the place we occupied before we went astray. Oh that we might never withdraw from the altar of entire consecration!