Digha Nikaya 1:1324
SUJATO“siyā kho pana, bhikkhave, ekabhikkhussāpi kaṅkhā vā vimati vā buddhe vā dhamme vā saṅghe vā magge vā paṭipadāya vā, pucchatha, bhikkhave, mā pacchā vippaṭisārino ahuvattha:
“Perhaps even a single mendicant has doubt or uncertainty regarding the Buddha, the teaching, the Saṅgha, the path, or the practice. So ask, mendicants! Don’t regret it later, thinking: