Avraham sits at the entrance to his tent waiting for guests. When the three angels arrive he runs out to greet them and pleads that they stay. He then tells them (Bereishit 18:4):
יֻקַּח-נָא מְעַט-מַיִם, וְרַחֲצוּ רַגְלֵיכֶם; וְהִשָּׁעֲנוּ, תַּחַת הָעֵץ
Please let a little water be taken, and bathe your feet, and recline under the tree
Rashi explains why they needed to wash their feet:
and bathe your feet: He thought that they were Arabs, who prostrate themselves to the dust of their feet, and he was strict not to allow any idolatry into his house. But Lot, who was not strict, mentioned lodging before washing, as it is said (below 19:2): “and lodge and bathe your feet.” - [from Gen. Rabbah 54:4]
Having said this, the Torah makes no mention of Avraham letting them enter his tent/house; it merely mentions that he offers them to 'recline under the tree'. Is there a reason for this discrepancy?