Adam Clarke on Psalms 41:2

The Lord will preserve him, and keep him alive - It is worthy of remark, that benevolent persons, who consider the poor, and especially the sick poor; who search cellars, garrets, back lanes, and such abodes of misery, to find them out, (even in the places where contagion keeps its seat), very seldom fall a prey to their own benevolence. The Lord, in an especial manner, keeps them alive, and preserves them; while many, who endeavor to keep far from the contagion, are assailed by it, and fall victims to it. God loves the merciful man.