Although the Church is tossed about on the sea, it rides easily on rivers, especially those rivers that Scripture speaks of: The rivers have lifted up their voice. These are the rivers flowing from the heart of the one who is given drink by Christ and who receives from the Spirit of God. When these rivers overflow with the grace of the Spirit, they lift up their voice.
There is also a stream which flows down on God’s saints like a torrent. There is also a rushing river giving joy to the heart that is at peace and makes for peace. Whoever has received from the fullness of this river, like John the Evangelist, like Peter and Paul, lifts up his voice. Just as the apostles lifted up their voices and preached the Gospel throughout the world, so those who drink these waters begin to preach the good news of the Lord Jesus.
Drink, then, from Christ, so that your voice may also be heard. Store up in your mind the water that is Christ, the water that praises the Lord. Store up water from many sources, the water that rains down from the clouds of prophecy.
Whoever gathers water from the mountains and leads it to herself or draws it from springs, is herself a source of dew like the clouds. Fill your soul, then, with this water, so that your land may not be dry, but watered by your own springs.
She who reads much and understands much, receives her fill. She who is full, refreshes others. So Scripture says: If the clouds are full, they will pour rain upon the earth.
A letter of St. Ambrose