Balasutta 2.3

2.3

Idha, bhikkhave, bhikkhu samādhissa samāpattikusalo hoti, samādhissa ṭhitikusalo hoti, samādhissa vuṭṭhānakusalo hoti, sakkaccakārī ca hoti, sātaccakārī ca, sappāyakārī ca.

It’s when a mendicant is skilled in entering immersion, skilled in remaining in immersion, and skilled in emerging from immersion. And they practice carefully and persistently, and do what’s suitable.