If you read the whole epistle, that verse seems to be implying that if you are 'in Christ', God will supply your 'every' need to persevere to the end!!!!!! Paul is not talking about God promising necessarily financial blessings, but of providing spiritual strength and blessings to go through all trials and tribulations for the sake of Christ. Financial blessings may or may not have come for many of those Paul wrote to. Many were 'baby' Christians (new in the faith) possibly dying of starvation and/or being persecuted for proclaiming Christ's name. PAUL wrote this letter from prison. He was worried about their response to his imprisonment and possibly their 'falling away' from the faith. Thus, the letter's focus is on the hearing of the good news that those he taught are bearing fruit in his absence (through the teaching by other capable men). The gifts Paul recieved from them were proof that God's Spirit was doing a good work in them and thus proof God was sustaining them in their faith. THAT WAS PAUL'S JOY!!!! Read the context of the whole letter to Philippi. Paul's greatest joy (THANKFULNESS) was to see Christ working in the hearts of those he preached to and providing them strength to endure some setbacks, including Paul's imprisonment..... THEIR FRUIT WAS BEING MANIFESTED AND THUS GOD WAS SUSTAINING THEM....If you go back to chapter 1 you will see it. It's what's called "bookends". The beginning of the letter and the end of the letter reflect the same thought.
Philipians 1:
3 I thank my God in all my remembrance of you, 4always in every prayer of mine for you all making my prayer with joy, 5 because of your partnership in the gospel from the first day until now. 6And I am sure of this, that he who began a good work in you will bring it to completion at the day of Jesus Christ. 7It is right for me to feel this way about you all, because I hold you in my heart, for you are all partakers with me of grace, both in my imprisonment and in the defense and confirmation of the gospel. 8For God is my witness, how I yearn for you all with the affection of Christ Jesus. 9And it is my prayer that your love may abound more and more, with knowledge and all discernment, 10so that you may approve what is excellent, and so be pure and blameless for the day of Christ, 11filled with the fruit of righteousness that comes through Jesus Christ, to the glory and praise of God.
Philipians 4:
9What you have learned and received and heard and seen in mepractice these things, and the God of peace will be with you.... ...12 I know how to be brought low, and I know how to abound. In any and every circumstance, I have learned the secret of facing plenty and hunger, abundance and need. 13 I can do all things through him who strengthens me.....14 Yet it was kind of you to share my trouble. Not that I seek the gift, but I seek the fruit that increases to your credit.18 I have received full payment, and more.....I am well supplied, having received from Epaphroditus the gifts you sent, a fragrant offering, a sacrifice acceptable and pleasing to God. 19 And my God will supply every need of yours according to his riches in glory in Christ Jesus. 20To our God and Father be glory forever and ever. Amen.....