Digha Nikaya 1:83
SUJATOYāvakīvañca, bhikkhave, bhikkhū na oramattakena visesādhigamena antarāvosānaṁ āpajjissanti, vuddhiyeva, bhikkhave, bhikkhūnaṁ pāṭikaṅkhā, no parihāni.
they don’t stop half-way after achieving some trifling distinction, they can expect growth, not decline.