Charles H. Spurgeon on Psalms 66:13

I will. The child of God is so sensible of his own personal indebtedness to grace, that he feels that he must utter a song of his own. He joins in the common thanksgiving, but since the best public form must fail to meet each individual case, he makes sure that the special mercies received by him shall not be forgotten, for he records them with his own pen, and sings of theme with his own lips. I will go into thy house with burnt offerings; the usual sacrifices of godly men. Even the thankful heart dares not come to God without a victim of grateful praise; of this as well as of every other form of worship, we may say, "the blood is the life thereof." Reader, never attempt to come before God without Jesus, the divinely promised, given, and accepted burnt offering. I will pay thee my vows. He would not appear before the Lord empty, but at the same time he would not boast of what he offered, seeing it was all due on account of former vows. After all, our largest gifts are but payments; when we have given all, we must confess, "O Lord, of thine own have we given unto thee." We should be slow in making vows, but prompt in discharging them. When we are released from trouble, and can once more go up to the house of the Lord, we should take immediate occasion to fulfil our promises. How can we hope for help another time, if we prove faithless to covenants voluntarily entered upon in hours of need.