Ubhayasutta
“Catasso imā, bhikkhave, paṭipadā. Katamā catasso? Dukkhā paṭipadā dandhābhiññā, dukkhā paṭipadā khippābhiññā, sukhā paṭipadā dandhābhiññā, sukhā paṭipadā khippābhiññā.
Both
“Mendicants, there are four ways of practice. What four? Painful practice with slow insight, painful practice with swift insight, pleasant practice with slow insight, and pleasant practice with swift insight.