Samyukta Āgama (2) 23
Māra disturbs a teaching on impermanence
Thus have I heard, once, the Buddha was staying north of Rājagaha in the Sītavana forest. At that time the Buddha told the monks: “Human life is short, it is bound to end. You should make an effort to follow the path and practice in purity and celibacy. Therefore do not be lazy; practice right conduct. You should train yourselves in the right meaning of the Dhamma and true conduct.”
At that time the Demon King Māra, having heard what was said, thought: “The renunciant Gotama is expounding the principles of the Dhamma for his disciples in the Sītavana forest at Rājagaha. I should go there and disturb them.” Having thought thus, he transformed himself into a young man and went to the Buddha. He paid homage at his feet and stood to one side. Then he spoke a verse:
Then King Māra, having heard the verse, thought: “The renunciant Gotama knows my intentions.” And he became depressed and dispirited and felt deep regret. He made himself invisible and returned to his heavenly palace.