en_tn_lite_do_not_use/2pe/03/06.md

through which

Here "which" refers to God's word and water.

the world at that time was destroyed, being flooded with water

This can be stated in active form. Alternate translation: "God flooded the world that existed at that time with water and destroyed it" (See: rc://en/ta/man/translate/figs-activepassive)