Philippians 1:21 – “For to me, to live is Christ, and to die is gain.”
Php 1:22 But if I live in the flesh, this is the fruit of my labour:
Paul is talking first about the "human powers in the flesh" the fruit of human powers, mean nothing to the Lord. Such powers must die.
Php 1:25 And having this confidence, I know that I shall abide and continue with you all for your furtherance and joy of faith;
Now Paul switches to another way to live, through the joy of faith
Php 1:29 For unto you it is given in the behalf of Christ, not only to believe on him, but also to suffer for his sake;
When you live by faith in Jesus, you also suffer for His sake, just as Jesus suffered for you sake, BECAUSE the Devil hates Faith in the Father,
Hence the Devil threaten you with death, so you cling to His faith of doing pious things using human powers, a Satanic faith that means nothing to the Lord.
Php 2:6 Who, being in the form of God, thought it not robbery to be equal with God:
7 But made himself of no reputation, and took upon him the form of a servant, and was made in the likeness of men:
8 And being found in fashion as a man, he humbled himself, and became obedient unto death, even the death of the cross.
Look what Jesus suffered when He had faith in His Father !!
Php 2:17 Yea, and if I be offered upon the sacrifice and service of your faith, I joy, and rejoice with you all.
Again Paul is talking about living in Jesus through faith.
Php 3:4 ¶ Though I might also have confidence in the flesh.
Living in the flesh in human power means nothing
Php 3:9 ¶ And be found in him, not having mine own righteousness, which is of the law, but that which is through the faith of Christ, the righteousness which is of God by faith:
Paul is talking about living in Jesus by faith
Php 4:13 I can do all things through Christ which strengtheneth me.
Shalom