Abraham planted a tamarisk tree at Beersheba, and there he called on the name of the Lord, the Everlasting God.
Genesis 21:33 (NASB)
Genesis 21 is the 3rd time the verb נָטַע (natah) “planted” shows up in the Bible.
The first time, it’s when God planted a garden in Eden. (Genesis 2:8)
The second time, Noah planted a vineyard after the Great Flood. (Genesis 9:20)
This time, Abraham plants a tamarisk tree and calls God “El Olam,” or “God Everlasting.”
Why plant a tree? What does it have to do with “Everlasting?” The text doesn’t say, but it may be connected to the use of “olam” in the text.
Genesis repeats the phrase “everlasting covenant” or “everlasting” with “your SEED” (Genesis 13:15, 17:7, 17:8, 17:13, 17:19).
Perhaps Abraham associates “seed” with “everlasting,” so we should understand that he planted the tree from a seed as a remembrance.