Why did the great masters and virtuous monks of the past generally not cite scriptures and classics when expounding the Dharma?

Question: Why did the patriarchs and great masters of the past generally not cite scriptural passages when expounding the Dharma? 

Answer: The patriarchs and great masters of the past were all genuinely accomplished, truly realized, and truly virtuous bodhisattvas who had genuinely attained enlightenment. Therefore, when expounding the Dharma, they spoke only from their own wisdom and insight, without seeking exhaustive elaboration, and without concealment; they spoke truthfully and reasoned in accordance with the Dharma. If they occasionally cited scriptural passages, it was either for those whose conditions were not yet ripe and who lacked sufficient faith-root and wisdom, or to use the Buddhist sutras as supplementary explanation when the Dharma meaning was profound. 

From another perspective, in ancient times, Dharma learners had relatively deep roots of goodness, with relatively good merit, meditative concentration, and wisdom, sufficient faith-root, and the eye of Dharma-selection, so they had the correct capacity for discernment and the capacity for faithful acceptance regarding the patriarchs' teachings. Therefore, the patriarch-bodhisattvas could expound the Dharma with confidence, speaking freely of what they knew through their own wisdom and realization, without any worries. Sentient beings today have shallow and scant roots of goodness, are deficient in merit, meditative concentration, and wisdom, lack sufficient faith-root, and lack the eye of Dharma-selection; many people would rather be deceived than take advice. Therefore, when expounding the Dharma, one must cite many scriptural passages to inspire faith. On the other hand, if the Dharma speaker's period of practice is short, without genuine wisdom and realization, and the Dharma meaning has not yet been thoroughly mastered, then they have no choice but to cite scriptural passages. Yet even when citing scriptural passages, first, sentient beings cannot understand them as they truly are, and second, the Dharma speaker has not thoroughly penetrated the sutras either, so misunderstandings and misinterpretations are still unavoidable. This is the result of sentient beings' karmic force; with heavy karma and meager merit (alpa-puṇya), the path of practice becomes winding and tortuous, advancing and retreating, with no knowing when it will reach its end.