Hebrews 5:1-10 Superior High Priest

How is Jesus similar / greater than the high priests of the Old Testament?  Note the repetition of Ps. 2 here (also 1:5).  Keep in mind the introduction of Melchizedek and Ps. 110 here – for ch. 7.  Again (see 2:10) “perfect” v.9 should read, “complete”.  Note the progression: Jesus greater than the high priest after the priesthood of Aaron – and now introducing – Jesus greater than the priesthood of Melchizedek (more to come in ch. 7).  How is Jesus “the source of salvation for all who obey Him”?  How do we “obey Him”?