1 Chronicles 17:13 - I will be His Father and He shall be my Son: and I will not take My mercy away from Him as I took it from him that was before thee
Hebrews 1:4-5 - Being made so much better than the angels, as He hath by inheritance obtsined a more excellent name than they. For unto which of the angels said he at any time, Thou art my Son, this day have I begotten Thee? And again, I will be to Him a Father, and He shall be to Me a Son?
In this passage in 1 Chronicles, God is promising that He will be a Father to David's seed. This seed was Jesus Christ. This is confirmed by the passage in Hebrews, which affirms that Christ is the Son of God and is higher in rank thsn the angels.