At Sāvatthī. Then Venerable Bāhiya went up to the Buddha, bowed, sat down to one side, and said to him: “Sir, may the Buddha please teach me Dhamma in brief. When I’ve heard it, I’ll live alone, withdrawn, diligent, keen, and resolute.” “Well then, Bāhiya, you should purify the starting point of skillful qualities. What is the starting point of skillful qualities? Well purified ethics and correct view. When your ethics are well purified and your view is correct, you should develop the four kinds of mindfulness meditation, depending on and grounded on ethics.

What four? Meditate observing an aspect of the body—keen, aware, and mindful, rid of covetousness and displeasure for the world. Meditate observing an aspect of feelings … mind … principles—keen, aware, and mindful, rid of covetousness and displeasure for the world. When you develop these four kinds of mindfulness meditation, depending on and grounded on ethics, you can expect growth, not decline, in skillful qualities, whether by day or by night.”