"And the LORD went before them" (Exodus 13:21). By the measure with which a person measures, by it they measure to him. Abraham escorted the ministering angels, as it is said: "And Abraham went with them to send them on their way" (Genesis 18:16). Therefore the Holy One, blessed be He, escorted His children in the wilderness for forty years. Abraham said: "Let now a little water be fetched" (Genesis 18:4).
The Parting Of The Red Sea
Tanchuma, Beshalach 4
וַה' הֹלֵךְ לִפְנֵיהֶם. בַּמִּדָּה שֶׁאָדָם מוֹדֵד, בָּהּ מוֹדְדִים לוֹ. אַבְרָהָם לִוָּה מַלְאֲכֵי הַשָּׁרֵת, שֶׁנֶּאֱמַר: וְאַבְרָהָם הֹלֵךְ עִמָּם לְשַׁלְּחָם. לְפִיכָךְ לִוָּה הַקָּדוֹשׁ בָּרוּךְ הוּא אֶת בָּנָיו בַּמִּדְבָּר אַרְבָּעִים שָׁנָה. אַבְרָהָם אָמַר יֻקַּח נָא.