Majjhima Nikaya 3:122
SUJATOYasmiṁ samaye, bhikkhave, bhikkhu vedanāsu …pe…
Whenever a mendicant meditates by observing an aspect of feelings …
Yasmiṁ samaye, bhikkhave, bhikkhu vedanāsu …pe…
Whenever a mendicant meditates by observing an aspect of feelings …