Today, we pick up our study in Galatians 3:15, “Brethren, I speak after the manner of men; Though it be but a man's covenant, yet if it be confirmed, no man disannulleth, or addeth thereto.” He compares the contracts that between man with the contract that He had with Abraham.
Notice v.16, “Now to Abraham and his seed were the promises made. He saith not, And to seeds, as of many; but as of one, And to thy seed, which is Christ.” The promise referred to here is found in Genesis 22:16-18 where it says, “And said, By myself have I sworn, saith the LORD, for because thou hast done this thing, and hast not withheld thy son, thine only son: That in blessing I will bless thee, and in multiplying I will multiply thy seed as the stars of the heaven, and as the sand which is upon the sea shore; and thy seed shall possess the gate of his enemies; And in thy seed shall all the nations of the earth be blessed; because thou hast obeyed my voice.” The Seed referred to here is the Messiah.
Notice v.17, “And this I say, that the covenant, that was confirmed before of God in Christ, the law, which was four hundred and thirty years after, cannot disannul, that it should make the promise of none effect.” The promise to Abraham was given 430 years before the giving of the Law, so the Law has no bearing on the promise.
Notice v.18, “For if the inheritance be of the law, it is no more of promise: but God gave it to Abraham by promise.” In other words, if the inheritance that was promised was conditional upon the Law than it was not a promise at all.
Notice v.19, “Wherefore then serveth the law? It was added because of transgressions, till the seed should come to whom the promise was made; and it was ordained by angels in the hand of a mediator.” So, the question now is, “If the Law did not set aside or even add to the promise that God made to Abraham what was the purpose of giving it at all?” It was added because of transgressions. Sin! Romans 4:15 says, “Because the law worketh wrath: for where no law is, there is no transgression.” Also, Romans 5:20 says, “Moreover the law entered, that the offence might abound. But where sin abounded, grace did much more abound:” So, the Law was to point out our falleness until the Messiah would come and offer a way to fix it. Romans 10:4 says, “For Christ is the end of the law for righteousness to every one that believeth.”
Evangelist Fred Brown used three images to describe the purpose of the law. First he likened it to a dentist's little mirror, which he sticks into the patient's mouth. With the mirror he can detect any cavities. But he doesn't drill with it or use it to pull teeth. It can show him the decayed area or other abnormality, but it can't provide the solution.
Brown then drew another analogy. He said that the law is also like a flashlight. If suddenly at night the lights go out, you use it to guide you down the darkened basement stairs to the electrical box. When you point it toward the fuses, it helps you see the one that is burned out. But after you've removed the bad fuse and inserted a new one, you turn off the flashlight as that it is no longer needed.
In his third image, Brown likened the law to a plumb line. When a builder wants to check his work, he uses a weighted string to see if it's true to the vertical. But if he finds that he has made a mistake, he doesn't use the plumb line to correct it. He gets out his hammer and saw. The law points out the problem of sin; it doesn't provide a solution. Of course, the mediator spoke of in this verse is referring to Moses.
Notice v.20, “Now a mediator is not a mediator of one, but God is one.” The very idea of a mediator implies that there are two parties involved. Of course, in the given of the Law, it was God and the People with Moses playing the mediator. However, when God made the covenant with Abraham, there was only one party; Himself (Genesis 15).