Commentary for Genesis 21:33

אשל [AND ABRAHAM PLANTED AN] אשל — Rab and Samuel differ as to what this was. One said it was an orchard from which to supply fruit for the guests at their meal. The other said it was an inn for lodging in which were all kinds of fruit (Sotah 10a). And we can speak of planting an inn for we find the expression planting used of tents, as it is said, (Daniel 11:45) “And he shall plant the tents of his palace”.

AND HE CALLED THERE IN THE NAME OF THE ETERNAL, ‘E-IL OLAM’ (THE EVERLASTING G-D). Scripture explains that Abraham called by the name Eternal He Who in His might directs the time.
It may be that heaven and earth are here being called olam (world) [so that the sense of the verse is, “he called by the name Eternal the G-d of the world”], as is a customary expression in the words of our Rabbis. Thus Scripture informs us by this that Abraham called out and informed people of the secret of the leadership of the entire world, namely, that it is in the name of the Eternal, the Mighty One in strength, Supreme in power over all.
Now the Rabbi³⁶²Rambam. See Seder Bereshith, Note 139. said in the Moreh Nebuchim³⁶³II, 13. See also III, 29. that this alludes to the principle of the pre-existence of G-d since Abraham let it be known that G-d existed before the creation of time. Onkelos, however, said of the word vayikra (and he called), that it refers to prayer.

ויטע אשל, an orchard. The presence of such an orchard should encourage people to pray to G’d there.