John Gill Commentary Hebrews 10:21

"and [having] a great priest over the house of God;" — Hebrews 10:21 (ASV)

And [having an] high priest over the house of God .
] The church of God, over which Christ is as prophet, priest, and King, and as the Son and owner of it; (See Gill on Hebrews 3:6); (See Gill on Hebrews 4:14). In the Greek text it is, "a great priest"; so the Messiah is called by the Targum on (Zechariah 6:12) (br Nhk) , "a great priest", as he is; even a great high priest, as in (Hebrews 4:14) , and greater than Aaron, and any of his sons.