Psalms 69:21

21.And they put gall into my meat. Here he again repeats that his enemies carry their cruelty towards him to the utmost extent in their power. He speaks metaphorically when he describes them as mingling gall or poison with his meat, (85) and vinegar with his drink; even as it is said in Jeremiah,

“Behold, I will feed them, even this people, with wormwood,
and give them water of gall to drink.” (Jeremiah 9:15)

But still the Apostle John justly declares that this Scripture was fulfilled when the soldiers gave Christ vinegar to drink upon the cross, (John 19:28;) for it was requisite that whatever cruelty the reprobate exercise towards the members of Christ, should by a visible sign be represented in Christ himself. We have stated on the same principle, in our remarks upon Psalms 22:18, that when the soldiers parted the garments of Christ among them, that verse was appropriately quoted, “They parted my garments among them, and upon my vesture did they cast lots;” although David’s object was to express by figurative language that he was robbed, and that all his goods were violently taken from him, and made a prey of by his enemies. The natural sense must, however, be retained; which is, that the holy prophet had no relief afforded him; and that he was in a condition similar to that of a man who, already too much afflicted, found, as an additional aggravation of his distress, that his meat was poisoned, and his drink rendered nauseous by the bitter ingredients with which it had been mingled.

Vinegar, we conceive, here means sour wine, such as was given to slaves or prisoners in the East. Persons in better circumstances used lemons or pomegranates to give their drink a grateful acidity. It was therefore a great insult offered to a royal personage to give him in his thirst the refreshment of a slave or of a wretched prisoner; and David employs this figure to express the insults which were offered to him by his enemies. See Harmer ’s Observations, volume 2, pp. 158, 159.