Genesis 28:20

Jacob vowed a vow That is, bound himself by a solemn promise and obligation. This being the first instance of a religious vow which occurs in Scripture, it may be proper to observe, that such a vow is a binding of the soul by a solemn and voluntary promise, made to God, to do, or more carefully to do a thing, which otherwise by our duty and God's law we are bound to do; or to do certain things, lawful in themselves, but otherwise left indifferent to be done or not; or to abstain from some things otherwise lawful to be used; and all this in a way of thankfulness to God for some extraordinary blessings received, (Jonah 1:16,) or for the obtaining of some special benefits which we greatly desire, and stand in need of, Numbers 21:1; Judges 11:30; 1 Samuel 1:2;

Proverbs 31:2. Jacob was now in fear and distress; and in times of trouble it is seasonable to make vows. Jacob had now a gracious visit from heaven, and when God ratifies his promises to us, it is proper for us to repeat our promises to him. If thou wilt be with me and keep me We need desire no more to make us easy and happy wherever we are, but to have God's presence with us, and to be under his protection. Then shall the Lord be my God Then I will believe, love, and rejoice in him as my God, and I will be the more strongly engaged to abide with him. And this pillar shall be God's house That is, an altar shall be erected here to the honour of God. And of all that thou shalt give me I will surely give the tenth unto thee To be spent either upon God's altars, or upon his poor, which are both his receivers in the world. The tenth is a very fit proportion to be devoted to God, and employed for him; though, as circumstances vary, it may be more or less, as God prospers us.