Rashi on TanakhJoel 3

And it shall come to pass afterwards—in the future.

upon all flesh—I.e, upon anyone whose heart becomes soft as flesh. Comp. (Ezekiel 36:26) “And I will give you a heart of flesh.”

and pillars of smoke Heb. וְתִימְרוֹת. Perpendicular pillars of smoke, as tall as a palm tree.

shall turn to darkness—to embarrass those who prostrate themselves to the sun.

And it shall come to pass that whoever shall call etc. as... said—And where did He say it? (Deut. 28:10), “And all the peoples of the earth shall see that the Name of the Lord is called on you.” [from Mechilta, Ex. 12:25]

and among the survivors—And in the remnant that will remain.

whom the Lord invites Heb. קֹרֵא, an expression of those invited to a banquet or to the service of the king, an expression of invitation.