11 Now will He speak openly of the same Sacrament, whereby He was carried in His Own Hands. “O taste and see that the Lord is good”. Does not the Psalm now open itself, and show you that seeming insanity and constant madness, the same insanity and sober inebriety of that David, who in a figure showed I know not what, when in the person of king Achis they said to him, How is it? When the Lord said, “Except a man eat My Flesh and drink My Blood, he shall have no life in him”? And they in whom reigned Achis, that is, error and ignorance, said; what said they? “How can this man give us his flesh to eat?” If you are ignorant, “Taste and see that the Lord is good:” but if you understand not, you are king Achis: David shall change His Countenance and shall depart from you, and shall quit you, and shall depart.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)