1: αἴτιος
(Strong's #159 — Adjective — aitios — ah'ee-tee-os )

an adjective (cp. aitia, a cause), denotes "that which causes something." This and No. 2 are both translated "author" in Hebrews. Aitios, in Hebrews 5:9 , describes Christ as the "Author of eternal salvation unto all them that obey Him," signifying that Christ, exalted and glorified as our High Priest, on the ground of His finished work on earth, has become the personal mediating cause (RV, margin) of eternal salvation. It is difficult to find an adequate English equivalent to express the meaning here. Christ is not the merely formal cause of our salvation. He is the concrete and active cause of it. He has not merely caused or effected it, He is, as His name, "Jesus," implies, our salvation itself, Luke 2:30; 3:6 .

2: ἀρχηγός
(Strong's #747 — Adjective — archegos — ar-khay-gos' )

translated "Prince" in Acts 3:15 (marg., "Author") and Acts 5:31 , but "Author" in Hebrews 2:10 , RV, "Captain," RV marg., and AV, and "Author" in Hebrews 12:2 , primarily signifies "one who takes a lead in, or provides the first occasion of, anything." In the Sept. it is used of the chief of a tribe or family, Numbers 13:2 (RV, prince); of the "heads" of the children of Israel, Numbers 13:3; a captain of the whole people, Numbers 14:4; in Micah 1:13 , of Lachish as the leader of the sin of the daughter of Sion: there, as in Hebrews 2:10 , the word suggest a combination of the meaning of leader with that of the source from whence a thing proceeds. That Christ is the Prince of life signifies, as Chrysostom says, that "the life He had was not from another; the Prince or Author of life must be He who has life from Himself." But the word does not necessarily combine the idea of the source or originating cause with that of leader. In Hebrews 12:2 where Christ is called the "Author and Perfecter of faith," He is represented as the one who takes precedence in faith and is thus the perfect exemplar of it. The pronoun "our" does not correspond to anything in the original, and may well be omitted. Christ in the days of His flesh trod undeviatingly the path of faith, and as the Perfecter has brought it to a perfect end in His own person. Thus He is the leader of all others who tread that path. See PRINCE.

1—Corinthians 14:33