Acts 13:33

that God has amply fulfilled it to our children in raising up Jesus; as it is also written in the second Psalm, 'Thou art My Son: to-day I have become Thy Father.'

Hebrews 5:5

So Christ also did not claim for Himself the honour of being made High Priest, but was appointed to it by Him who said to Him, "My Son art Thou: I have to-day become Thy Father;"

Hebrews 1:5-6

For to which of the angels did God ever say, "My Son art Thou: I have this day become Thy Father;" and again, "I will be a Father to Him, and He shall be My Son"?

Treasury of Scripture Knowledge

Summary

God hath fulfilled the same unto us their children, in that he hath raised up Jesus again; as it is also written in the second psalm, Thou art my Son, this day have I begotten thee.

Bible References

Thou art

Hebrews 1:5
For to which of the angels did God ever say, "My Son art Thou: I have this day become Thy Father;" and again, "I will be a Father to Him, and He shall be My Son"?
Hebrews 5:5
So Christ also did not claim for Himself the honour of being made High Priest, but was appointed to it by Him who said to Him, "My Son art Thou: I have to-day become Thy Father;"