Not that I seek the gift, but I seek the fruit that increases to your credit. (ESV)
How much money is in your bank account? I imagine most people would answer, "Not enough!" I worked in banks for a number of years. I have had thousands of dollars pass through my hands, but not many of those dollars made their way into my account. And now, as I look forward to retirement I fear that there are still not many dollars stored up for me.
I want to ask a different question. How much spiritual money is stored up for you in your eternal account? Have you ever considered that? The Apostle Paul certainly did. Here in this verse he tells the Philippian believers that when it comes to them giving a gift to help his ministry he is more interested in them getting credit eternally. He seeks the fruit that increases to their credit.
What does it mean that we have credit that increases. The reality is that when we give of our resources to the work of the Lord there is an increase to our eternal credit. We are giving up resources here on earth, but our loving Heavenly Father will reward us in Heaven. I doubt those rewards will be money, as I doubt there will be money needed in heaven, but I can imagine his reward is far greater.
Listen to Jesus' words. He speaks to this very concept of treasure in Heaven:
 but lay up for yourselves treasures in heaven, where neither moth nor rust destroys and where thieves do not break in and steal. (ESV)
Be very wise with how you invest your life. We can get so consumed with earthly treasure. Increase your spiritual bank account by obediently giving to the work of spreading the Gospel.