A.T. Robertson Commentary Philippians 1:6

"being confident of this very thing, that he who began a good work in you will perfect it until the day of Jesus Christ:" — Philippians 1:6 (ASV)

Being confident (πεποιθως). Second perfect active of πειθω, to persuade.

This very thing (αυτο τουτο). Accusative of the inner object with πεποιθως, "this thing itself."

Will perfect it (επιτελεσε). Future active indicative of επιτελεω, will fully (επι-) finish. God began and God will consummate it (see 2 Corinthians 8:6; Galatians 3:3 where both words occur together as here), but not without their cooperation and partnership.

Until the day of Jesus Christ (αχρ ημερας Χριστου Ιησου). The second coming as in verse 10. See 1 Thessalonians 5:2,4; 2 Thessalonians 1:10; 2:2; 1 Corinthians 1:18; 3:13; 2 Corinthians 1:14; Romans 13:12. Paul never sets the time for the Lord's return, but he is cheered by that blessed hope.