This was because the people of Ammon and Moab did not give food and water to the Israelites on their way out of Egypt. Instead, they paid money to Balaam to curse Israel, but our God turned the curse into a blessing.
“Now, mortal man, prophesy. Clap your hands, and the sword will strike again and again. It is a sword that kills, a sword that terrifies and slaughters.
that a people who came from Egypt has spread out over the whole land. He wants me to curse them for him, so that he can fight them and drive them out.”
They outnumber us, so please come and put a curse on them for me. Then perhaps we will be able to defeat them and drive them out of the land. I know that when you pronounce a blessing, people are blessed, and when you pronounce a curse, they are placed under a curse.”
The nation is like a mighty lion; When it is sleeping, no one dares wake it. Whoever blesses Israel will be blessed, And whoever curses Israel will be cursed.”