Augustine of Hippo

Observe "the waters of Babylon." "The waters of Babylon" are all things which here are loved, and pass away. ...But then other citizens of the holy Jerusalem, understanding their captivity, mark how the natural wishes and the various lusts of men hurry and drag them hither and thither, and drive them into the sea; they see this, and they throw not themselves into the waters of Babylon, but "sit down and weep," either for those who are being carried away by them, or themselves whose deserts have placed them in Babylon, but sitting, that is, humbling themselves. O holy Sion, where all stands firm and nothing flows! Who hath thrown us headlong into this? Why have we left thy Founder and thy society? Behold, placed where all things are flowing and gliding away, scarce one, if he can grasp the tree, shall be snatched from the stream and escape. Humbling ourselves then in our captivity, let us "sit by the waters of Babylon," let us not dare to plunge ourselves in those streams, nor to be proud and lifted up in the evil and sadness of our captivity, but let us sit, and so weep. Let us sit "by" the waters, not beneath the waters, of Babylon; such be our humility, that it overwhelm us not. Sit "by" the waters, not "in" the waters, not "under" the waters; but yet sit, in humble fashion, talk not as thou wouldest in Jerusalem. ...For many weep with the weeping of Babylon, because they rejoice also with the joy of Babylon. When men rejoice at gains and weep at losses, both are of Babylon. Thou oughtest to weep, but in the remembrance of Sion. If thou weepest in the remembrance of Sion, thou oughtest to weep even when it is well with thee in Babylon.