"Now you Philippians know also that in the beginning of the gospel, when I departed from Macedonia, no church shared with me concerning giving and receiving but you only. For even in Thessalonica you sent aid once and again for my necessities" (Phil. 4:15-16).
Paul had a very special relationship with the church at Philippi. The whole book of Philippians illuminates this fact (see Phil. 1:3-5 for example), but here at the close of the book, the apostle gives us yet another example of their loving fellowship. You see, there weren't any churches who provided Paul with financial support while he preached the gospel, at least not in the early part of his ministry...except for the church at Philippi. They loved him dearly and were cognizant of his needs as he preached and ministered in other regions.
Of course, we learn here that it is Scriptural for the local church to support evangelists abroad, but the point that I'd like to emphasize is in verse 16 where Paul adds that the Philippians sent him aid "once and again."
So often, when we hear of someone who is in need (whether it be physical or spiritual), we "send them aid" once and that's it. If it's a physical hardship, we may go and visit them in the hospital just once. If it's a financial hardship, we may send them a Wal-Mart gift card just once. If it's a spiritual hardship, we may call them and encourage them just once. But then we get swept away by the business of our own lives, and we tell ourselves that at least we reached out to them once.
But you know as well as I do that hardship is not always short-lived. Sometimes, folks will struggle, not just for a day or week, but for a month, or for several months. Don't forget about those who are in need. Remind yourself that they may be in constant need of encouragement and aid. Call them often. Visit them often. Regularly check in with them regarding their needs. In other words, do what the Philippians did to Paul almost 2,000 years ago - send them aid once and again.