John Gill Bible Commentary

For the bed is shorter than that a man can stretch himself on it,.... When a bed is short, a man cannot lie at his full length, and at ease: and the covering narrower than that he can wrap himself in it; when the bedclothes are narrow a man cannot cover himself with them, so as to be warm and comfortable. These proverbial expressions are interpreted by Kimchi of Jerusalem, when besieged by the Assyrian army, when the inhabitants of it were much straitened, distressed, and made uncomfortable; perhaps it may be better understood of the same city when besieged by the Romans, to which the Jews flocked from all parts, in such numbers, for shelter, that there was not room enough for them, at least not provision, and which was the cause of that great distress and miserable condition they were reduced to: in general, the design of the words may be to show that all refuges and shelters, all means made use of for safety and protection, by which they endeavoured to cover and secure themselves, would be insufficient; and particularly such that laid themselves at ease on the bed of their own righteousness, not submitting to Christ and his righteousness, and covered themselves with the rags of their own doings, and not with the garments of his salvation, would find themselves in a very uncomfortable and unsafe state.