Better [is it] that thou shouldest not vow, than that thou shouldest vow and not pay.
Ver. 5. Better it is that thou shouldest not vow,] q.d., Who bade thee be so forward? Why wouldst thou become a voluntary votary, and so rashly engage to the loss of thy liberty and the offence of thy God, who expected thou shouldst have kept touch, and not have dealt thus slipperily with him? a "Thou hast not lied unto men, but unto God." Act 5:4 "As the truth of Christ is in me," saith Paul; 2Co 11:10 so he binds himself by an oath, as the learned have observed. And "as God is true, our word toward you was not yea and nay; for the Son of God who was preached among you by me was not yea and nay; but in him all the promises of God are yea and amen." 2Co 1:19-20 Why, what of that? some might say; and what is all this to the purpose? Very much, for it implieth that what a Christian doth promise to men (how much more to God?) he is bound by the earnest penny of God's Spirit to perform. He dares no more alter or falsify his word than the Spirit of God can lie. And as he looks that God's promises should be made good to him, so is he careful to pay what he hath vowed to God, since his is a covenant of mercy, ours of obedience; and if he shall be all-sufficient to us, we must be altogether his. Son 2:16
a Dicta factis deficientibus crubescunt.