Jerusalem Water Yoel 4 commentators

Radak on Joel 4:18

And in that day – At that time, after the nations are consumed, there will be a great good for Israel there. The prophet compared the goodness they will have without effort or toil to mountains which drip wine and hills that flow with milk. The reason he uses the word ‘telachna’ in reference to the milk, is that due to the quantity of the flow pouring out its passage is called hills, even though the milk is flowing. So too in regard to water it says ‘yelchu’ and that flow is called watercourses. In the same manner it says “…so that our eyes may shed tears…” (Jeremiah 9:17) The water courses are the valleys in which the water flows: A spring shall issue from the House of the Lord – this is according to its plain meaning, as is written in the prophecy of Ezekiel. And will water the Valley of Shittim – As it is translated into Aramaic – the valley of acacias. A valley is called a stream (nachal) whether there is water in it or not, as in “And Isaac's servants dug in the valley (nachal)…” (Bereshit 26:19) And in the words of the Sages, the one who sits in the valley. Rav Saadia Gaon said that the valley of Shittim is the Jordan, because the Jordan is close to the place called Shittim, therefore they put the names together.

Malbim Yoel 4:18

And in that day – The outpouring and blessing will increase so powerfully to the point that the hills will drip wine from the masses of sweet fruit and the hills will flow with milk from the abundance of sheep and cattle. All the watercourses of Yehudah will flow with water, because until now water was lacking throughout the land, and in Jerusalem where there were no springs. Then, not only will there be water in Yehudah, but also a spring will flow from the house of the Lord. From there a source will be opened, rising and spreading outwards until it waters the river of Shittim. According to R’ Saadia Gaon this refers to the Jordan that is close to Shittim, and Rashi read it literally. Ezekiel and Zechariah already prophesied about this spring. A different level of meaning is that from there Torah, and faith which is compared to water, will emanate to the whole world. Furthermore, since at Shittim the children of Israel broke out into harlotry and idolatry with ba’al peor and this was the beginning of since for the house of Israel – he indicates that the holy spring will purify the impurity which began at the river of Shittim, removing the desires and strange evils.