A Zen master on Mount Wutai once took on a disciple who was only three years old at the time. Mount Wutai is extremely high, and the master and disciple practiced on the summit, never descending the mountain. After more than ten years, the master and the disciple descended the mountain together. The young monk saw cows, horses, chickens, and dogs but didn’t know what they were.
The master pointed and told him, “This is a cow, used for plowing fields.