Ecclesiastes 1:7

All the rivers run into the sea; yet the sea is not full - The reason is, nothing goes into it either by the; rivers or by rain, that does not come from it: and to the place whence the rivers come, whether from the sea originally by evaporation, or immediately by rain, thither they return again; for the water exhaled from the sea by evaporation is collected in the clouds, and in rain, etc., falls upon the tops of the mountains; and, filtered through their fissures, produce streams, several of which uniting, make rivers, which flow into the sea. The water is again evaporated by the sun; the vapors collected are precipitated; and, being filtered through the earth, become streams, etc., as before.

The place - i. e., The spring or river-head. It would seem that the ancient Hebrews regarded the clouds as the immediate feeders of the springs (Proverbs 8:28, and Psalm 104:10, Psalm 104:13). Genesis 2:6 indicates some acquaintance with the process and result of evaporation.

1:7 Is not full - So as to overflow the earth. Whereby also he intimates the emptiness of mens minds, notwithstanding all the abundance of creature comforts. Rivers come - Unto the earth in general, from whence they come or flow into the sea, and to which they return by the reflux of the sea. For he seems to speak of the visible and constant motion of the waters, both to the sea and from it, and then to it again in a perpetual reciprocation.