Ps 136:6

“"Let my tongue cleave to my jaws, if I remember not you" [Psalm 137:6]. That is, let me be dumb, he says, if I remember not you. For what word, what sound does he utter, who utters not songs of Sion? That is our tongue, the song of Jerusalem. The song of the love of this world is a strange tongue, a barbarous tongue, which we have learned in our captivity. Dumb then will he be to God, who forgets Jerusalem. And it is not enough to remember: for her enemies too remember her, desiring to overthrow her. "What is that city?" say they; "who are the Christians? What sort of men are the Christians? Would they were not Christians." Now the captive band has conquered its capturers; still they murmur, and rage, and desire to slay the holy city that dwells as a stranger among them. Not enough then is it to remember: take heed how you remember. For some things we remember in hate, some in love. And so, when he had said, "If I forget you, O Jerusalem," etc., he added at once, "if I prefer not Jerusalem in the height of my joy." For there is the height of joy where we enjoy God, where we are safe of united brotherhood, and the union of citizenship. There no tempter shall assail us, no one be able so much as to urge us on to any allurement: there nought will delight us but good: there all want will die, there perfect bliss will dawn on us.”