{It became him} (eprepen aut(9369)). Imperfect active of
prep(935c), old verb to stand out, to be becoming or seemly. Here it
is impersonal with 	elei(9373)ai as subject, though personal in
 Heb 7:26 . Aut(9369) (him) is in the dative case and refers to
God, not to Christ as is made plain by 	on arch(8867)on (author).
One has only to recall  Joh 3:16  to get the idea here. The
voluntary humiliation or incarnation of Christ the Son a little
lower than the angels was a seemly thing to God the Father as the
writer now shows in a great passage ( 2:10-18 ) worthy to go
beside  Php 2:5-11 . {For whom} (di' hon). Referring to aut(9369)
(God) as the reason (cause) for the universe (	a panta).
{Through whom} (di' hou). With the genitive dia expresses the
agent by whom the universe came into existence, a direct
repudiation of the Gnostic view of intermediate agencies (aeons)
between God and the creation of the universe. Paul puts it
succinctly in  Ro 11:36  by his ex autou kai di' autou kai eis
auton ta panta. The universe comes out of God, by means of God,
for God. This writer has already said that God used his Son as
the Agent (di' hou) in creation ( 1:2 ), a doctrine in harmony
with  Col 1:15f.  (en aut(9369), di' autou eis auton) and  Joh
1:3 . {In bringing} (agagonta). Second aorist active participle
of ag(935c) in the accusative case in spite of the dative aut(9369)
just before to which it refers. {The author} (	on arch(8867)on).
Old compound word (arch(885c) and ag(935c)) one leading off, leader or
prince as in  Ac 5:31 , one blazing the way, a pioneer (Dods) in
faith ( Heb 12:2 ), author ( Ac 3:15 ). Either sense suits here,
though author best (verse  9 ). Jesus is the author of salvation,
the leader of the sons of God, the Elder Brother of us all ( Ro
8:29 ). {To make perfect} (	elei(9373)ai). First aorist active
infinitive of 	eleio(935c) (from 	eleios). If one recoils at the
idea of God making Christ perfect, he should bear in mind that it
is the humanity of Jesus that is under discussion. The writer
does not say that Jesus was sinful (see the opposite in  4:15 ),
but simply that "by means of sufferings" God perfected his Son in
his human life and death for his task as Redeemer and Saviour.
One cannot know human life without living it. There was no moral
imperfection in Jesus, but he lived his human life in order to be
able to be a sympathizing and effective leader in the work of
salvation.