Dutiyasikkhattayasutta 3.2

3.2

Idha, bhikkhave, bhikkhu vivicceva kāmehi …pe… catutthaṃ jhānaṃ upasampajja viharati.

It’s when a mendicant, quite secluded from sensual pleasures, secluded from unskillful qualities, enters and remains in the first absorption … second absorption … third absorption … fourth absorption.