Commentary for Isaiah 12:3

And you shall draw water You shall receive a new teaching [from Targum].

And you will draw water. By this figure the prophet indicates that they will rejoice exceedingly, as the thirsty rejoices when he draws water.

from the fountains of the salvation For their heart will be dilated through the salvation that came to them, and secrets of the Torah that have been forgotten during the exile, because of the troubles, will be revealed to them.