"...he who began a good work in you will carry it on to completion until the day of Christ Jesus."
How reassuring it is to know and to hear that it is God (not me) who began His work of salvation in me, and that it is also God (NOT ME) who will complete His work of salvation in me!
We (correctly) teach the Bible saying that it is God who saved us by His grace. But after that we inadvertently (incorrectly) teach that it is up to us to make sure we don't lose our salvation and blow it! With such thoughts and teachings, we are guilt ridden when we sin, and we guilt trip other Christians and "squeeze" them when we communicate that they are not living "up to par" or living as they should. In Php 1:6, Paul is crystal clear that the work of salvation begins with God, and that is is completed by God (not by me, or by Paul). The NT emphasizes this over and over again, repeatedly (Php 1:29, 2:13; Eph 2:1,5; Col 2:13; Jn 1:12; Acts 11:18; 2 Th 2:13-14; Heb 11:29, 40).