Charles Spurgeon Commentary Galatians 3:17-20

"Now this I say: A covenant confirmed beforehand by God, the law, which came four hundred and thirty years after, doth not disannul, so as to make the promise of none effect. For if the inheritance is of the law, it is no more of promise: but God hath granted it to Abraham by promise. What then is the law? It was added because of transgressions, till the seed should come to whom the promise hath been made; [and it was] ordained through angels by the hand of a mediator. Now a mediator is not [a mediator] of one; but God is one." — Galatians 3:17-20 (ASV)

They zealously affect you, but not well; yea, they would exclude you, that ye might affect them. But it is good to be zealously affected always in a good thing, and not only when I am present with you. My little children, of whom I travail in birth again until Christ be formed in you, I desire to be present with you now, and to change my voice; for I stand in doubt of you.

The point of doubt was that they had been led astray by legal teachers; they had been made to believe that, after all, there was something in outward ceremonies, something in the works of the law, and so they had come under bondage again. So the apostle says, –