Genesis 49:22 - Joseph Benson’s Commentary on the Old and New Testaments

Joseph is a fruitful bough Shooting forth two luxuriant stems or branches, the two numerous tribes which proceeded from his sons; by a well Or fountain, or water-course, where plants grow fastest. Thus David compares a godly man to “a tree planted by the rivers of waters:” Whose branches run over the wall The heat of which furthers their growth no less than the moisture received from the water.