Hebrews 5:6

Just as elsewhere he says, Thou art a priest for ever, with the rank of Melchizedek.

Hebrews 7:17

for the witness to him is, Thou art priest for ever, with the rank of Melchizedek.

Hebrews 7:21

Previous priests became priests apart from any oath, but he has an oath from Him who said to him, The Lord has sworn, and he will not change his mind, thou art a priest for ever.

Hebrews 5:10

being designated by God high priest with the rank of Melchizedek.

Hebrews 6:20

There Jesus entered for us in advance, when he became high priest for ever with the rank of Melchizedek.

Hebrews 7:3

He has neither father nor mother nor genealogy, neither a beginning to his days nor an end of his life, but, resembling the Son of God, continues to be priest permanently.

Hebrews 7:15

This becomes all the more plain when another priest emerges resembling Melchizedek,

Treasury of Scripture Knowledge

Summary

As he saith also in another place, Thou art a priest for ever after the order of Melchisedec.

General references

Bible References

Thou

Hebrews 5:10
being designated by God high priest with the rank of Melchizedek.
Hebrews 6:20
There Jesus entered for us in advance, when he became high priest for ever with the rank of Melchizedek.
Hebrews 7:3
He has neither father nor mother nor genealogy, neither a beginning to his days nor an end of his life, but, resembling the Son of God, continues to be priest permanently.

General references

Hebrews 5:10
being designated by God high priest with the rank of Melchizedek.
Hebrews 7:17
for the witness to him is, Thou art priest for ever, with the rank of Melchizedek.