[156] Bhikkhus, a bhikkhu endowed with three qualities is adequate for himself but not for others. What three? Here, bhikkhus, a bhikkhu is not one who quickly grasps wholesome teachings (dhammas); but he is one who retains in mind the teachings he has heard; he is one who examines the meaning (attha) of the teachings he has retained; and, having understood the meaning and understood the Dhamma, he is one who practices in accordance with the Dhamma. But he is not of lovely speech, not a maker of lovely utterance, not endowed with urbane speech that is articulate, flawless, and communicates the meaning; and he is not one who instructs, encourages, inspires, and gladdens his fellow practitioners of the holy life (sabrahmacārī). Endowed with these three qualities, bhikkhus, a bhikkhu is adequate for himself but not for others.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.