Skillful & Unskillful
Kusal’akusala Sutta  (AN 2:19)

“Abandon what is unskillful, monks. It is possible to abandon what is unskillful. If it were not possible to abandon what is unskillful, I would not say to you, ‘Abandon what is unskillful.’ But because it is possible to abandon what is unskillful, I say to you, ‘Abandon what is unskillful.’ If this abandoning of what is unskillful were conducive to harm and pain, I would not say to you, ‘Abandon what is unskillful.’ But because this abandoning of what is unskillful is conducive to benefit and pleasure, I say to you, ‘Abandon what is unskillful.’

“Develop what is skillful, monks. It is possible to develop what is skillful. If it were not possible to develop what is skillful, I would not say to you, ‘Develop what is skillful.’ But because it is possible to develop what is skillful, I say to you, ‘Develop what is skillful.’ If this development of what is skillful were conducive to harm and pain, I would not say to you, ‘Develop what is skillful.’ But because this development of what is skillful is conducive to benefit and pleasure, I say to you, ‘Develop what is skillful.’”

See also: SN 22:2; Iti 39