Psalms 41:3

The Lord will support him upon the couch of languishing (R.V.), uphold him (Psalms 18:35) and preserve him from sinking into the grave.

thou wilt make all his bed Lit. thou hast turned (or, changed) his lying down: changed his sickness into health. Cp. Psalms 30:11. Instead of a general truth a particular example is appealed to: or perhaps faith pictures the result as already attained. -The Lord will support … nay, thou hast already raised him up."

The verse is commonly explained as a metaphor from the nurse supporting the patient's head and shifting the bed and pillows to give ease and relief, but usage does not seem to warrant this interpretation.