3 Without father or mother, without genealogy, without beginning of days or end of life, resembling the Son of God, he remains a priest forever.

Read Hebrews 7:3 Using Other Translations

Without father, without mother, without descent, having neither beginning of days, nor end of life; but made like unto the Son of God; abideth a priest continually.
He is without father or mother or genealogy, having neither beginning of days nor end of life, but resembling the Son of God he continues a priest forever.
There is no record of his father or mother or any of his ancestors—no beginning or end to his life. He remains a priest forever, resembling the Son of God.