Verse 7: And the LORD said unto Joshua, This day will I begin to (Josh. 4:14; 1 Chron. 29:25; 2 Chron. 1:1) magnify thee in the sight of all Israel, that they may know that, (Josh. 1:1) as I was with Moses, so I will be with thee.
[I will begin to exalt thee] It acquires a name for the Ruler, if the subordinates understand that he is carried in the bosom of God. He is not able not to be thought the best or most prudent, to whom God is near at hand in all things (Masius).
This day will I begin to magnify thee, etc.: To gain thee authority and reputation among them, as the person whom I have set in Moses’s stead, and by whom I will conduct them to the possession of the promised land.
[That they may known] אֲשֶׁר is in the place of לְמַעַן, to the intent that (Vatablus).
[Just as I was with Moses] In splitting the sea, so I will be with thee in splitting the Jordan (Drusius). From Moses to Saul, God was demonstrating either by miracles, or deeds exceeding human expectation, whom He willed to be the Princes of His people (Grotius).
 Hebrew: וַיֹּ֤אמֶר יְהוָה֙ אֶל־יְהוֹשֻׁ֔עַ הַיּ֣וֹם הַזֶּ֗ה אָחֵל֙ גַּדֶּלְךָ֔ בְּעֵינֵ֖י כָּל־יִשְׂרָאֵ֑ל אֲשֶׁר֙ יֵֽדְע֔וּן כִּ֗י כַּאֲשֶׁ֥ר הָיִ֛יתִי עִם־מֹשֶׁ֖ה אֶהְיֶ֥ה עִמָּֽךְ׃
 Hebrew: אֲשֶׁר֙ יֵֽדְע֔וּן.