Malachi told everyone another message from God:
Listen to this dude, cuz he’s my messenger. One day, y’all are going to get a surprise visit from me, and you ain’t gonna like it. I mean, no one can really live up to my standards, and you think y’all will live through my visit? I’m gonna purify all those shitty priests and their shitty offerings! I’m sick of you guys skimping on the good stuff! Where my tithes at? If you want good harvests, then you better pay up! I make it rain, yo!
Also, quit bitching about if evildoers prosper, then I’m not real. You don’t know my ways, yo! And I’m, like, omniscient and omnipotent and stuff. So just believe that justice will prevail, on some dimensional plane or other!
But wait, there’s more! When I come to town, I’m will destroy sorcerers, of course. But I also hate cheaters and liars, so I will destroy anyone who’s ever cheated on their spouse and any one who ever swore falsely–don’t swear to god unless you mean it, yo! I also hate the fact that rich humans are dicks to poor humans, so I will destroy shitty bosses who treat their workers bad and don’t pay them enough and anyone who mistreats or oppresses poor single women and their children. Also, y’all have been immigrants! People who mistreat immigrants are the worst, and they will feel my wrath, too.
So everyone was like, well since this Malachi dude says he’s speaking from God and is preparing the way for all this punishment, we better take him seriously! So they wrote all that he said down in a book so they could remember it and promised that they would do their best to please God from then on.