The LORD will strengthen him upon the bed of languishing: thou wilt make all his bed in his sickness.
The Lord will strengthen him upon the bed of languishing - The Lord will sustain him by supplying strength, consolation, patience, etc.
Thou wilt make all his bed in his sickness. "Make" - literally, turn. The image is that of a most tender nurse turning the bed of the patient, in order that he may lie the more easily. The idea meant is, God will mitigate the trial of the merciful man in various ways, and change his position of pain into one of tranquillity. The "bed" means the state of the sufferer. "All his bed" means, as often soever as he is afflicted; and howsoever great may be his affliction, God completely assuages it.
Here the sufferer, who can claim the promise of mercy to the merciful (Psalms 41:1-3), pleads before God his distressed state, and the malice of his enemies, as a ground for the promise being fulfilled now.