Matthew Poole's Concise Commentary
Isaiah 58:5
That I have chosen; approve of, accept, or delight in, by a metonymy, because we delight in what we freely choose. A day for a man to afflict his soul; or, to afflict his soul for a day. It is an hypallage, and so it may be understood either for a man to take a certain time to afflict his soul in, and that either from even to even, Leviticus 23:32, or from morning to evening, Judges 20:26 2 Samuel 3:35; or else to afflict his soul for a little time. To afflict, or keep himself low, or chastise the body for want of food, viz. outwardly, without any inward sorrow, or compunction for sin, working a true humiliation in the sight of God. His soul, put here synecdochically for the body or person, as is usual in Scripture, Genesis 46:18,22,25 Le 5:2,4 7:20,21,27 22:11. To bow down his head as a bulrush: here the prophet sets down those external gestures and postures in particular which they did join with their hypocritical fasts, as he had mentioned it before in general. To bow down; bowing is the posture of mourners, Psalms 35:14; and here it is either, as if through weakness of body their heads did hang down; or counterfeitly, to represent the posture of true penitents, moving sometimes their heads this way, and that way, as the word signifieth, not unlike the balance of a clock, as the bulrush moved by the wind boweth itself down, waving to and fro, in a kind of circular or semicircular motion; the contrary motion of lifting up the head being an indication of pride, Isaiah 3:16. It is the guise of hypocrites to put on affected countenances, Mt 6 16. To spread sackcloth and ashes under him. The Jews, to express their sorrow, made use of sackcloth and ashes two ways.
1. Sometimes by putting on sackcloth upon their bodies, as 1 Kings 21:27 Psalms 69:11, and casting ashes upon their heads, 2 Samuel 13:19. And,
2. Sometimes by spreading sackcloth under them, and lying down upon ashes, Esther 4:3 Job 2:8. The intent of sackcloth was to afflict the body by its unpleasing harshness, and of ashes to represent their own vileness, as being but dust and ashes; their putting of them on might note their uneasiness under sin, and laying on them their self-abhorrency, shaming themselves for it. Quest. Are such rites now convenient on a day of humiliation to help us in our afflicting of ourselves? Answ. Gospel services neither require them nor need them, respecting more the inward afflicting of the soul with godly sorrow and deep contrition; yet may they carry this instruction along with them, that our ornaments, our best and gaudy apparel, ought to be laid aside, as not suiting either the ground and cause, or the end and design, of days of humiliation. Wilt thou call this a fast? i.e. canst thou upon a rational account as a mere man call it so? canst thou think, suppose, or believe it to be so? it being such a one as has nothing in it but the lifeless skeleton and dumb signs of a fast, nothing of deep humiliation appearing in it, or real reformation proceeding from it. Not that the prophet blames them for these external rites in this outward way of afflicting themselves; for, this he commands, Leviticus 23:27,31,32, and appoints certain rites to be used, Leviticus 16:19 21. And these particular rites were frequent in their solemn humiliations, 1 Kings 21:27 Esther 4:3 Daniel 9:3; used also by the heathen, Jonah 3:5,6. See Matthew 11:21. But that which he condemns is their hypocrisy in separating true humiliation from them, for bodily exercise profiteth little, 1 Timothy 4:8. An acceptable day to the Lord; a day that God will approve of, as before. Heb. a day of acceptance, or that will turn to a good account on your behalf.