11 Being filled with the fruits of righteousness, which are by Jesus Christ, unto the glory and praise of God.

[Being filled with the fruits of righteousness] By righteousness we may understand here the whole work of the Spirit of God in the soul of a believer; and by the fruits of righteousness, all holy tempers, holy words and right actions. And with these they are to be filled, filled up, filled full; the whole soul and life occupied with them, ever doing something by which glory is brought to God or good done to man.

[By Jesus Christ] That is, according to his doctrine, through the power of his grace and by the agency of his Spirit.

[Unto the glory and praise of God] God is honored when the work of his grace appears to men in the fruits of righteousness; and God is praised by all the faithful when his work thus appears. Every genuine follower of God has his glory in view by all that he does, says or intends. He loves to glorify God, and he glorifies him by showing forth in his conversation the glorious working of the glorious power of the LORD.

12 But I would ye should understand, brethren, that the things which happened unto me have fallen out rather unto the furtherance of the gospel;

[The things which happened unto me] Paul was at this time a prisoner at Rome and it appears probable that he had already been called to make a defence for himself and to vindicate the doctrines of the Gospel; and this he had been enabled to do in such a manner that the honor of the Gospel had been greatly promoted by it. As the Philippians loved him greatly, he felt it right to give them this information relative to his state, and how God had turned his bonds to the advantage of that cause on account of which he was bound.

13 So that my bonds in Christ are manifest in all the palace, and in all other places;

[My bonds... are manifest in all the palace] In consequence of the public defence which he was obliged to make, his doctrines must be fully known in the court and throughout the whole city, as on his trial he would necessarily explain the whole. The praetorium, which is here translated palace, signifies the court where causes were heard and judged by the praetor, or civil magistrate; it sometimes signifies the general's tent, and at others, the emperor's palace. It is supposed that it is used in this latter sence here. There were, no doubt, persons belonging to the emperor's household who would bring the news of so remarkable a case to the palace; for we find that there were Christians even in Caesar's household; chapter 4:22.

14 And many of the brethren in the Lord, waxing confident by my bonds, are much more bold to speak the word without fear.

[Waxing confident] Finding the effect produced by the public defence which the apostle made, they were greatly encouraged, and the more boldly and openly proclaimed the doctrine of Christ crucified.

[The word] The doctrine of Christ: several excellent manuscripts add, "of the Lord" or "of God." This is a respectable reading and is probably genuine.

15 Some indeed preach Christ even of envy and strife; and some also of good will:

[Some... preach Christ even of envy and strife] These must have been Judaizing teachers who insisted on connecting the Mosaic rites with the Christian institutions; and, probably, denounced Paul to the Jews dwelling at Rome as not only an enemy to the law and the prophets, but also as a very imperfect Christian, because he declared strongly against the doctrine of circumcision, and no doubt endeavored to prejudice him with the heathen Romans.
The word preach is not to be taken as implying that the different persons mentioned here were what we call preachers of the Gospel. All that we can understand from Paul's use of the word is that they proclaimed Christ as the the promised Messiah, espoused the Christian cause and contended, whether in public or private, that this Jesus was the Christ; but nothing of this appears to have been intended in reference to the conversion of sinners.

[Some also of good will] Some, through mere benevolence to the apostle, both espoused his doctrine and vindicated his cause.

16 The one preach Christ of contention, not sincerely, supposing to add affliction to my bonds:

[Preach Christ of contention] The Judaizing teachers, they also preach Christ; they acknowledge that Jesus is the Christ or promised Messiah, and preach him as such.

[Not sincerely] Garbling the Gospel; not speaking the whole truth but just what served their purpose; and at the same time they denounced the apostle as an enemy of the Divine institutions because he spoke aginst circumcision.

17 But the other of love, knowing that I am set for the defence of the gospel.

[The other of love] Through a sincere desire, not only to make known the way of salvation to the people but also to vindicate and help the apostle because they considered him as appointed by God to preach and defend the Gospel.

18 What then? notwithstanding, every way, whether in pretence, or in truth, Christ is preached; and I therein do rejoice, yea, and will rejoice.

[What then?] It is a matter of little importance to me how Christ be preached, provided he be preached. I rejoice that anything is known of him; and am truly glad that the Gospel is even made partially known, for this will lead to further inquiries, and in the end can be of service to the truth.

19 For I know that this shall turn to my salvation through your prayer, and the supply of the Spirit of Jesus Christ,

[That this shall turn to my salvation] That is: It will be the means of my temporal safety; of my deliverance; for so the word is here to be understood. The Jews had pronounced the apostle as an enemy of Caesar, but he knew that when the nature of the Gospel should be fully known, the Romans would see that he could be no enemy to Caesar who proclaimed a prince whose kingdom is not of this world; and who taught, in the most unequivocal manner, that all Christians should give tribute to whom tribute was due, and while they feared God, to give honor to the king, though that king was Nero.

[Through your prayer] Knowing them to be genuine followers of Christ he was satisfied that their prayers would be very available in his behalf; and under God he places much dependence upon them.

[The supply of the Spirit of Jesus Christ] The word which is translated supply signifies also supplying whatever is necessary. Paul expected the Spirit of God to help all his infirmities, and to furnish him with all wisdom, prudence, strength of reason and argument which might be necessary for him in the different trials he had to pass through with his persecutors and the evil powers at whose judgement seat he stood.

20 According to my earnest expectation and my hope, that in nothing I shall be ashamed, but that with all boldness, as always, so now also Christ shall be magnified in my body, whether it be by life, or by death.

[Earnest expectation] He had the most confident expectation that God would stand by him so that he should be enabled, with the utmost liberty of speech, to testify the Gospel of the grace of God; and, should he have the liberty of doing so, he was utterly unconcerned what the result might be regarding himself. Life or death was to him perfectly equal and perfectly indifferent, providing Christ were magnified - his person, nature and doctrine shown to be what they really are, most noble, most excellent, most necessary and most glorious.

21 For to me to live is Christ, and to die is gain.

[For to me to live is Christ] Whether I live or die, Christ is gain to me. While I live I am Christ's property and servant, and Christ is my portion. If I die - if I be called to witness the truth at the expense of my life, this will be gain; I shall be saved from the remaining troubles and difficulties in life, and be put immediately in posession of my heavenly inheritance. Therefore, as regarding myself, it is a matter of perfect indifference to me whether I be taken off by a violent death, or whether I be permitted to continue here longer; in either case I can lose nothing.

22 But if I live in the flesh, this is the fruit of my labour: yet what I shall choose I wot not.

[But if I live in the flesh] Should I be spared longer, I shall labor for Christ as I have done; and this is the fruit of my labor, that Christ shall be magnified by my longer life.

[Yet what I shall choose I wot not] If I should have to choose, whether to die now and go to glory, or to live longer in persecutions and afflictions (glorifying Christ by spreading the Gospel,) I can not tell which I prefer.

23 For I am in a strait betwixt two, having a desire to depart, and to be with Christ; which is far better:
24 Nevertheless to abide in the flesh is more needful for you.

It would certainly be gain to myself to die, but it would be gain to you if I live. If I die I shall go immediately to glory; if I live I shall continue to minister to you and strengthen you in the faith.

25 And having this confidence, I know that I shall abide and continue with you all for your furtherance and joy of faith;

[Having this confidence] Convinced that it is necessary that I should live longer, for the spreading and defence of the Gospel, I am pursuaded that I shall now be liberated.

26 That your rejoicing may be more abundant in Jesus Christ for me by my coming to you again.

That was in fact the case, for, having been two years in the bonds of Rome, he was released.

27 Only let your conversation be as it becometh the gospel of Christ: that whether I come and see you, or else be absent, I may hear of your affairs, that ye stand fast in one spirit, with one mind striving together for the faith of the gospel;
28 And in nothing terrified by your adversaries: which is to them an evident token of perdition, but to you of salvation, and that of God.
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;
30 Having the same conflict which ye saw in me, and now hear to be in me.

The church at Philippi was under persecution. When Paul had preached the gospel at Philippi he was grievously persecuted as we learn from Acts 16:19-40, being stripped, scourged, thrown into prison, even into the dungeon, and his feet made fast in the stocks. This was the conflict they had seen in him and now they heard that he had been sent prisoner to Rome as an evil doer, that at present he was in bonds and shortly to be tried for his life before the Roman emperor.
Paul's confidence in the will of God was an example for them.