ציטירנדיקער פּירוש אויף יואל 3:1

The second question on what it says “The vision of Isaiah the son of Amoz”, If this statement included all the prophecies in this book, as it appears from its plain meaning, how could he refer to all of them as ‘the vision’ in the singular form? It would have been more appropriate to say ‘the visions of Isaiah’ according to the phrase ‘your young men shall see visions’ (Yoel 3:1) or ‘the words of Isaiah,’ as in the case of Jeremiah, who did not use the term ‘vision’ for all of his prophecies, but only for one prophecy, like “The vision of Obadiah” (Obadiah 1:1) which is one prophecy.

והתהלכתי בתוככם, "And I will walk among you." This is best understood as reflecting the promise of the prophet in Yoel 3,1 that "your sons and daughters will all prophesy." G'd's Light will walk among them i.e. a reference to the spirit of prophecy. This reminds us of Moses' wish that all the Jewish people should be granted the spirit of prophecy (Numbers 11,29).

Until...be poured upon us (יֵעָרֶה) He shall pour upon us. Comp. (Gen. 24:2) “And she emptied (וַתְּעַר) her pitcher.” An expression of pouring applies to spirit. Comp. (Zech. 12:10) “And I will pour upon the house of David...a spirit of grace.” Comp. also (Joel 3:1) “I will pour My spirit upon all flesh.”