Samyukta Āgama (2) 41
Sakka pays obeisance to the Buddha 2 (Dhamma)
At that time the World-honored One told the monks: “A long time ago Sakka Devānaṃ Inda wanted to go for a ride and enjoy his parkland. He ordered his charioteer Mātali: “Harness the thousand-horse chariot!” Soon Mātali harnessed the chariot, went to Sakka, and said to him: “The chariot is ready. We may leave whenever you please.” Thereupon Sakka left the Vejayanta Palace and with palms together paid obeisance facing south. When Mātali saw this, his mind was filled with surprise and fear, and he dropped the whip and reins.
Sakka said: “What have you seen that you are so scared?” Mātali said: “Maghavā! Husband of Sujā! When I saw you with palms together paying obeisance facing south, my mind became filled with fear and I dropped the whip and reins. All beings revere you; all the kings are under your rule. The four heavenly kings and the thirty-three gods all respectfully revere you. Who then surpasses you in power, that you stand and pay obeisance with palms together facing south?” Sakka answered: “I am revered by everyone, this may be as you say. However, all gods and human beings respectfully venerate the Dhamma. I respectfully pay obeisance to the perfect Discipline and Dhamma.” And Sakka spoke a verse:
The Buddha told the monks: “Sakka is powerful among men and gods. If even he pays obeisance to the Dhamma, how much more should you, monks, who have shaved off your hair and beard, left home to train in the path, how much more diligent should you be in paying obeisance to the Dhamma!”