Why was the lack of water a dilemma for Israel in the wilderness?
Israel's lack of water was a dilemma because many million people and all their livestock were in the hot Middle Eastern Sinai desert after three days without finding water; at Marah the water was bitter and undrinkable, leaving no drinkable supply.
Les explains that Moses brought Israel from the Red Sea after they crossed and the waters drowned the Egyptians, then led the multitude toward Mount Sinai. They went into the wilderness of Shur for three days and found no water. Les notes this was a dilemma because many million people and all their livestock were in the hot Middle Eastern Sinai desert with no water. At Marah, an oasis, the water was bitter and undrinkable. Les also points out that new believers soon after salvation can run into a bitter experience.
So Moses brought Israel from the Red sea, and they went out into the wilderness of Shur; and they went three days in the wilderness, and found no water.