This refers to an event when Yahweh made water miraculously flow out of a rock. God told Moses to speak to the rock. Instead, Moses hit the rock because he was angry with the people. (See: [[rc://en/ta/man/jit/figs-explicit]])
Here the people of the people are represented by their "eyes" to emphasize what they saw. Alternate translation: "in front of the whole community" (See: [[rc://en/ta/man/jit/figs-synecdoche]])