1. Sikkhā Sutta. The three forms of training in the higher insight. A.i.235.
2. Sikkhā Sutta. One must train oneself in the Dhamma. S.ii.131.
3. Sikkhā Sutta. A monk who returns to the lower life must blame himself for five things: having no faith in right things, no conscientiousness, no fear of blame, no energy, no insight into right things. A.iii.4.