(Above, verse 3) "And Abram fell on his face" (Genesis 17:3). Two times Abram fell on his face; corresponding to this, circumcision was taken away from his descendants two times, one in Egypt and one in the wilderness. In Egypt Moses came and circumcised them; in the wilderness Joshua came and circumcised them.
Abraham Fell Twice and Circumcision Lapsed Twice
Yalkut Shimoni on Torah 81:14
(לעיל פסוק ג) "וַיִּפֹּל אַבְרָם עַל פָּנָיו", שְׁנֵי פְּעָמִים נָפַל אַבְרָם עַל פָּנָיו כְּנֶגֶד כֵּן נִטְּלָה מִילָה מִבָּנָיו שְׁתֵּי פְּעָמִים, אֶחָד בְּמִצְרַיִם, וְאֶחָד בַּמִּדְבָּר. בְּמִצְרַיִם בָּא מֹשֶׁה וּמָלָן, בַּמִּדְבָּר בָּא יְהוֹשֻׁעַ וּמָלָן.