Paul had just stated that "...death was gain" but he was willing to keep living as long as the Lord wanted him to. He didn't just "give up" when everybody probably thought "he had done enough." This is an old theme but one that needs repeating. A dedicated believer doesn't stop serving the Lord even when their body wears out and they feel they would just like to die and go home! I'm sure many a believer felt that way shortly before their death. I personally have stayed by the bedside of quite a number of Christians who were "ready to go home." And most of them, if not all, had served Christ faithfully far beyond the normal "work life" of most humans.
Paul somehow knew God had more for him to do. And he was not only willing to go on living, but he was also willing to go on serving. He had said in Acts 20:24, "But none of these things move me; nor do I count my life dear to myself, so that I may finish my race with joy..." When he wrote to the Philippians he knew that he hadn't "crossed the finish line" yet. He was willing to keep going even if it meant literally wearing his body out for Christ.
I don't want to deny any hard working person the opportunity to get some rest in their elderly years. From a human standpoint, they deserved it. But Paul's attitude, as expressed in our Daily Verse, suggested that he didn't look at a certain age to be the time to "hang up his tools" and just sit back and rock himself into a grave. No! He knew he had more work to do and he would rather die serving than die sitting.