Hebrews 7:23-25 And they truly were many priests, because they were not suffered to continue by reason of death: But this man, because he continued ever, had an unchangeable priesthood. Wherefore he is able also to save them to the uttermost that come unto God by him, seeing he ever lived to make intercession for them. 

‘Unchangeable priesthood’ – A priesthood not passed to another, as in the Aaronic priesthood (7:23-24).

‘Wherefore he is able also to save them to the uttermost that come unto God by him seeing he ever lived to make intercession for them.’ Because He is an everlasting priest and has made the only true atonement for sin, He can save from all sin to the uttermost, in all places, at all times, and under all circumstances. The condition of salvation is coming to God by Him.

‘Intercession’ [Greek: entungchano] to light upon; fall in with; meet with; intercede with and for. Translated as “intercession” (7:25; Rom. 8:27, 34; 11:2) and “deal with” (Acts 25:24). Seven purposes of intercession: To come to or meet a person for any cause whatever (7:25; Rom. 8:27, 34). To plead the cause of others as in a civil court (Isa. 59:9-18; 1Tim. 2:1). To pray for others (Isa. 53:12; Luke 22:44; Rom. 8:26-27, 8:34; Heb. 7:25). To defend or vindicate a person or thing (Jer. 7:16; 27:18; 36:25). To commend others to a person (Rom. 8:26-27). To furnish any kind of assistance or help (Rom. 8:26-27). To accuse or act against a person in a judicial way (Rom. 11:2; Acts 25:24).