[157] [67] "Bhikkhus, a bhikkhu endowed with three qualities is adequate for the benefit of others, but not for his own. What three? Here, bhikkhus, a bhikkhu is not quick in grasping wholesome dhammas, yet he is one who retains the dhammas he has heard — this is one; he is not one who examines the meaning of the dhammas he has retained, nor, having understood the meaning and understood the dhamma, is he one who practises in accordance with the Dhamma, yet he is one of kindly and convincing speech (kalyāṇavāca), … endowed with speech able to communicate the meaning — this is another; and he instructs, encourages, inspires, and gladdens his companions in the holy life — this is another. Endowed with these three qualities, bhikkhus, a bhikkhu is adequate for the benefit of others, but not for his own."
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.