Adam Clarke on Philippians 2:21

For all seek their own - This must relate to the persons who preached Christ even of envy and strife, Phi 1:15; these must be very careless whether souls were saved or not by such preaching; and even those who preached the Gospel out of good will might not be fit for such an embassy as this, which required many sacrifices, and consequently much love and zeal to be able to make them.