I'm trying to find a specific story in where the Buddha spoke about the attainment of one Anagami lay person with a group of monks while praising his good qualities. Later, when those monks went for alms at his place, they informed him that the Buddha had spoken about his attainment. Then he asked the monks, if there were any lay persons present when the Buddha revealed it. The monks reported this back to the Buddha when they returned to the temple. Then the Buddha praised him again and said that is also another good quality of him.
I've heard this story several times in sermons, when the question comes up, whether an enlightened being would reveal his attainment to others.