for the work of Christ - namely, the bringing of a supply to me, the minister of Christ. He was probably in a delicate state of health in setting out from Philippi; but at all hazards he undertook this service of Christian love, which cost him a serious sickness.
not regarding his life - Most of the oldest manuscripts read, “hazarding,” etc.
to supply your lack of service - Not that Paul would imply, they lacked the will: what they “lacked” was the “opportunity” by which to send their accustomed bounty (Phi 4:10). “That which ye would have done if you could (but which you could not through absence), he did for you; therefore receive him with all joy” [Alford].