Jeremiah 5:22

When I say "we," I do not refer to human power but to the grace of God, who in the weakness of people shows forth his own power. This the prophet, speaking in the person of the Lord, says, "Will not you, then, fear me? I have set the sand as the boundary for the sea." For by this weakest and most contemptible of all things, sand, the mighty One has bound the great and ponderous sea. Therefore, since our condition is somewhat similar, it would follow that some of the true brethren should be sent continuously from your charity to visit us in our afflictions and that affectionate letters should come more frequently to us, on the one hand to strengthen our zeal, and on the other to correct us if we fail in any respect. Indeed, we do not deny that we are subject to many faults, since we are people and are living in the flesh.

And again God demanded from the Jews the fear of Himself by the hand of Jeremiah, and reproached them by the testimony of the dumb things in nature, which, though silent, trembled at the fear of Him, while the Jews despised His commandments. "Fear ye not Me? saith the Lord: will ye not tremble at My presence? For I have placed the sand for the bound of the sea, [by] an everlasting law, and it shall not pass over it." And here again the Creator demanded fear and trembling from created things, and because they forsook His fear they were reproached through the dumb things of nature, which feared and trembled at the Majesty of the Creator, while His commandments were despised by the children of men. And God in all places shewed the majesty of His nature by the hand of the Prophet, that He might cast the fear thereof into those who listened. For to those who would have despised His meekness----if it had been shewn unto them----He revealed the majesty of His nature that they might tremble thereat; and to others He shewed His gentleness and meekness, which at the report of His humiliation would increase [their] love [for Him].

Through all the story of waters be mindful of that first word, "Let the waters be gathered." It was necessary for them to flow that they might reach their own place. Then, being in the places appointed, they were to remain by themselves and not to advance further. For this reason, according to the saying of Ecclesiastes, "All the rivers run into the sea, yet the sea does not overflow." It is through the divine command that waters flow, and it is due to that first legislation, "Let the waters be gathered into one place," that the sea is enclosed within boundaries. For fear that the flowing water, spreading beyond the beds that hold it, always passing on and filling up one place after another, should continuously flood all the lands, it was ordered to be gathered into one place. Therefore, the sea, frequently raging with the winds and rising up in waves to towering heights, whenever it merely touches the shores breaks its onrush into foam and retires. "Will you not then fear me, says the Lord? I have set the sand as a bound for the sea." With the weakest of all things, sand, the sea, irresistible in its violence, is bridled.