Mt 1:21, Lk 1:32-33, 1 Cor 1:30
In the Old Testament, God promised to send His righteousness, Christ, to save us. (Jeremiah 23:5-6)
Jeremiah 23:5 Behold, the days come, saith the Lord, that I will raise unto David a righteous Branch, and a King shall reign and prosper, and shall execute judgment and justice in the earth. 6 In his days Judah shall be saved, and Israel shall dwell safely: and this is his name whereby he shall be called, The Lord Our Righteousness.
Jesus is the Christ, the righteousness of God who will save us whom God promised to send in the Old Testament. (Matthew 1:2, Luke 1:32-33, 1 Corinthians 1:30)
Matthew 1:2 Abraham begat Isaac; and Isaac begat Jacob; and Jacob begat Judas and his brethren;
Luke 1:32-33 He shall be great, and shall be called the Son of the Highest: and the Lord God shall give unto him the throne of his father David: 33 And he shall reign over the house of Jacob for ever; and of his kingdom there shall be no end.
1 Corinthians 1:30 But of him are ye in Christ Jesus, who of God is made unto us wisdom, and righteousness, and sanctification, and redemption: