The Worst Trade in History
Passage: Galatians 3:15–26
Charles Spurgeon - “Unless the Holy Ghost blesses the Word, we who preach the gospel are of all men most miserable, for we have attempted a task that is impossible. We have entered on a sphere where nothing but the supernatural will ever avail. If the Holy Spirit does not renew the hearts of our hearers, we cannot do it. If the Holy Ghost does not regenerate them, we cannot. If He does not send the truth home into their souls, we might as well speak into the ear of a corpse.”
The Law and the Promise
 To give a human example, brothers: even with a man-made covenant, no one annuls it or adds to it once it has been ratified.  Now the promises were made to Abraham and to his offspring. It does not say, “And to offsprings,” referring to many, but referring to one, “And to your offspring,” who is Christ.  This is what I mean: the law, which came 430 years afterward, does not annul a covenant previously ratified by God, so as to make the promise void.  For if the inheritance comes by the law, it no longer comes by promise; but God gave it to Abraham by a promise.
 Why then the law? It was added because of transgressions, until the offspring should come to whom the promise had been made, and it was put in place through angels by an intermediary.  Now an intermediary implies more than one, but God is one.
 Is the law then contrary to the promises of God? Certainly not! For if a law had been given that could give life, then righteousness would indeed be by the law.  But the Scripture imprisoned everything under sin, so that the promise by faith in Jesus Christ might be given to those who believe.
 Now before faith came, we were held captive under the law, imprisoned until the coming faith would be revealed.  So then, the law was our guardian until Christ came, in order that we might be justified by faith.  But now that faith has come, we are no longer under a guardian,  for in Christ Jesus you are all sons of God, through faith. (ESV)