We meet a man in Genesis called Abraham. He has great faith and trust in the Lord. The Lord promises him a son but Abraham and his wife Sarah are old.
So Abraham decides to take the promise into his own hands. He sleeps with Sarah’s servant and a son is born. They name him Ishmael. But he is not the son of a promise, instead he is a son of a slave. The Lord had promised that Sarah would give birth to a son, not her servant Hagar. Genesis 17:21 –
“But I will establish my covenant with Isaac, whom Sarah shall bear to you at this time next year.”
Galatians paints us a picture of why this is important:
Now the promises were made to Abraham and to his offspring. It does not say, “And to offspring’s,” referring to many, but referring to one, “And to your offspring,” who is Christ. (Galatians 3:16 ESV)
We are already waiting for an offspring and that offspring must come from the line of promise. The offspring cannot come from slavery but from sonship. Through his sonship he is going to offer us a great adoption:
But when the fullness of time had come, God sent forth his Son, born of woman, born under the law, to redeem those who were under the law, so that we might receive adoption as sons. And because you are sons, God has sent the Spirit of his Son into our hearts, crying, “Abba! Father!” So you are no longer a slave, but a son, and if a son, then an heir through God. (Galatians 4:4-7 ESV)
We are slaves and its only through this offspring can we be sons. His adoption of us means we are heirs, we can call on God as Father and it means we are no longer slaves – we are free.
If the promise came through a slave then there would be no sonship to offer. But Jesus offers the perfect adoption for us to be sons.
Christmas is about slaves becoming sons through the chosen offspring.