The Bible does not record any teaching yet, but they called him Rabbi which means Teacher. Perhaps it was a title of honor and they just wanted to show respect. Maybe they were startled by his question, but they didn't say, "John says you are the Lamb of God, and we want to hear about that."
They only said, "Where are you staying?" A mundane question, but it might let them know where he would be in the future or an opening for further conversation.
He wanted to maintain the open door, too. "Come and see," he said. They stayed the rest of the day; that might mean 6:00 or suppertime or bedtime. In any case, it was time for a longer conversation.
- What do you want to ask?
- What does Jesus say to you do when you are alone?
- What does it mean to be the Lamb of God?