6. confident--This confidence nerves prayers and thanksgivings (Php 1:3, 4).
      this very thing--the very thing which he prays for (Php 1:4) is the matter of his believing confidence (Mr 11:24; 1Jo 5:14, 15). Hence the result is sure.
      he which hath begun--God (Php 2:13).
      a good work--Any work that God begins, He will surely finish (1Sa 3:12). Not even men begin a work at random. Much more the fact of His beginning the work is a pledge of its completion (Isa 26:12). So as to the particular work here meant, the perfecting of their fellowship in the Gospel (Php 1:5; Ps 37:24; 89:33; 138:8; Joh 10:28, 29; Ro 8:29, 35-39; 11:1, 2 Heb 6:17-19; Jas 1:17; Jude 24). As God cast not off Israel for ever, though chastening them for a time, so He will not cast off the spiritual Israel (De 33:3; Isa 27:3; 1Pe 1:5).
      perform it until--"perfect it up to" [ALFORD, ELLICOTT, and others].
      the day of . . . Christ-- (Php 1:10). The Lord's coming, designed by God in every age of the Church to be regarded as near, is to be the goal set before believers' minds rather than their own death.

JFB.