“Satta Jatilā Sutta: Discourse on Seven Matted-hair Ascetics (Jatilā)“
In this sutta, the Lord Buddha warns about the impostors. Some people claim they are arahants, but they are not. That reminds me a lot of fake Bhikkhus today. The Buddha said we must associate with someone for a long time and observe his behavior before trusting him.
“Great king, as a layman enjoying worldly sense pleasures, living in a home with wives and children, enjoying the use of sandalwood, decorating the body with flowers, scents, and perfumes, and using gold and money, it is difficult for you to know who are Arahants and who are practicing the path to becoming Arahants.”