Acts 13:33

that the promise made unto the fathers God hath fulfilled unto us their children, having raised up Jesus again: as it is also written in the second psalm, "Thou art my Son, this day have I begotten thee."

Hebrews 5:5

So also Christ did not glorify himself to be made an high-priest; but He that said unto Him, "Thou art my Son, this day have I begotten thee."

Hebrews 1:5-6

For to which of the angels did He ever say, "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?"

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 He ever say, "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?"
Hebrews 5:5
So also Christ did not glorify himself to be made an high-priest; but He that said unto Him, "Thou art my Son, this day have I begotten thee."