Why do these reactions happen? As an example, when we hit a child, the child will cry due to the pain inflicted on him or her; when people are happy or sad, they too will cry. But the tears this time come from being overwhelmed by the truth.

Whether it is tears or laughter is unimportant. What is essential is to experience this state of mind.

~Depicted from THE FOUR SEALS OF DHARMA - The Practice of Realizing Emptiness