15:60 What means “…We have decreed…”?

‏السلام عليكم ورحمة الله وبركاته جميعا They said, “We have been sent to a wicked people (15:58) — Ruwwad Center except the household of Lot; we will surely save them all (15:59) — Ruwwad Center Except his wife; We decreed that she is of those who remain behind”. (15:60) — Ruwwad Center because of the sign ‘ “” ‘ , we see that the speech belongs to the angels. In this context “decreed” means a collective decision? please give correct understanding brothers, I ask before you answer me, please read carefully. I know that the plural also means greatness. It's plural here with a capital letter, to indicate that it is from Allah, as I believe. and if not difficult give an example ‏جزاكم الله خيرا