As said above, prudence is concerned with particular practicables. As such things are almost infinitely diverse, no one man can adequately consider them all, nor in a short time rather than through a long period of time. Thus in things relevant to prudence, man especially needs to be taught by others, and particularly by elders, who have achieved sensible understanding of practicable ends [qui sanum intellectum adepti sunt circa fines operabilium]. Thus the Philosopher says, in VI Ethic., "It is fitting to attend no less to the indemonstrable claims and opinions of experienced people who are older and prudent, than to their demonstrations, for by experience they see principles." Thus also it is said in Prov. III, "Do not lean on your own prudence"; and it is said in Eccli. VI, "Stand in the multitude of presbyters, that is, elders, that are prudent, and join yourself from the heart to their wisdom." And this pertains to teachableness [docilitas], to be very receptive to learning. And so teachableness is appropriately posited as a part of prudence.
You can read the Dominican Fathers translation here.
