Rom 1:2, Gal 3:16, Rom 10:4, Rom 15:8-12
God made promises about His Son through the prophets in the Old Testament. (Rom 1:2)
Rom 1:2 (Which he had promised afore by his prophets in the holy scriptures,)
It is Christ that God promised to Abraham and his descendants. (Gal 3:16)
Gal 3:16 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 law given by God was also fulfilled in Christ. (Rom 10:4)
Rom 10:4 For Christ is the end of the law for righteousness to every one that believeth.
It was in Christ that God called both the Israelites and the Gentiles. (Rom 15:8-12)
Rom 15:8 Now I say that Jesus Christ was a minister of the circumcision for the truth of God, to confirm the promises made unto the fathers: 9 And that the Gentiles might glorify God for his mercy; as it is written, For this cause I will confess to thee among the Gentiles, and sing unto thy name. 10 And again he saith, Rejoice, ye Gentiles, with his people. 11 And again, Praise the Lord, all ye Gentiles; and laud him, all ye people. 12 And again, Esaias saith, There shall be a root of Jesse, and he that shall rise to reign over the Gentiles; in him shall the Gentiles trust.
All of God's promises have been fulfilled in Christ. So we glorify God through Christ. (2 Cor 1:19-20)
2 Cor 1:19 For the Son of God, Jesus Christ, who was preached among you by us, even by me and Silvanus and Timotheus, was not yea and nay, but in him was yea. 20 For all the promises of God in him are yea, and in him Amen, unto the glory of God by us.