Musar do Samuela II 23:6

In the world there are trees and herbs and good and bad fruit. Some of them have a pleasant aroma and fruit that is good for nourishment and healing. And there are herbs and roots and fruit that can slay, like the herbs which produce deadly poison or like the thorn and the thistle. The good flora may be compared to good people, as it is written, "As a lily among thorns… As an apple tree among the trees of the wood" (Cant. 2:2—3). And the evil flora to evil people, as it is written, "But the ungodly, they are as thorns thrust away" (II Sam. 23:6).