Philo Judaeus Quod Deterius Potiori Insidiari Soleat 108

[108] and from these two shoots one single tree of one united nature sprang up, each portion giving to the other that which was useful to it; for the roots support the shoot which has been fitted into them, and prevent it from drying up and withering, and the shoot which has been inserted as a reward for its nourishment supplies the root with good fruit in requital. There are also an innumerable host of other operations in farming which proceed on rules of art, which it would be superfluous to enumerate on the present occasion, for we have only dwelt on this point at such length for the purpose of showing the difference between the man who is only a cultivator of the earth, and one who is a farmer.