'Things' in the Bible

Now I want to remind you, even though you are fully aware of these things, that the Lord who once saved his people from the land of Egypt later destroyed those who did not believe.

Whatever these people do not understand, they slander. Like irrational animals, they are destroyed by the very things they know by instinct.

15He will judge all people and convict everyone of all the ungodly things that they have done in such an ungodly way, including all the harsh things that these ungodly sinners have said about him."

These people are complainers and faultfinders, following their own desires. They say arrogant things and flatter people in order to take advantage of them.