So also it is good not always to make a friend of the person who is expert in twining himself around us; but, after testing them, to attach ourselves to those who are worthy of our affection and likely to be serviceable to us.
PlutarchNature without learning is like a blind man; learning without Nature, like a maimed one; practice without both, incomplete. As in agriculture a good soil is first sought for, then a skilful husbandman, and then good seed; in the same way nature corresponds to the soil, the teacher to the husbandman, precepts and instruction to the seed.
Plutarch