Not a hair fall from the head - A proverbial expression, denoting "that they would be preserved safe; that none of them would be lost, and that "in their persons they should not experience the least damage," 1-Kings 1:52; 1-Samuel 14:45.

A hair fall from the head - A proverbial expression for, ye shall neither lose your lives nor suffer any hurt in your bodies, if ye follow my advice.

Wherefore I pray you to take [some] meat: for this is for your health: for there shall not an (g) hair fall from the head of any of you.
(g) This is a proverb which the Hebrews use, by which is meant that they will be safe, and that not one of them will perish.

Wherefore I pray you to take some meat,.... To sit down composedly, and eat meat cheerfully and freely:
for this is for your health; the Alexandrian copy reads, "for our health"; it was for the health of them all, that they might be better able to bear the shock and fatigue of the shipwreck, and be in better spirits, and in a better capacity to help themselves, and one another:
for there shall not an hair fall from the head of any of you; a proverbial phrase, expressing the utmost safety of their lives, and therefore might cheerfully eat their food, and rest themselves, and be satisfied. To dream of shaving the hair, portended shipwreck to sailors; nor was it lawful for any to pare his nails, or cut off his hair, but in a storm; to which custom, some think, the apostle here alludes (w); see 1-Samuel 14:45.
(w) Kirchman. de funer. Romans. l. 2. c. 14. p. 212, 213.

I pray you to take some meat, for this is for your health, for there shall not a hair fall from . . . any of you--On this beautiful union of confidence in the divine pledge and care for the whole ship's health and safety see on Acts 27:31.

This is for your preservation - That ye may be the better able to swim to shore.