9:7-21 There was no occasion for the trees to choose a king, they are all the trees of the Lord which he has planted. Nor was there any occasion for Israel to set a king over them, for the Lord was their King. Those who bear fruit for the public good, are justly respected and honoured by all that are wise, more than those who merely make a figure. All these fruit-trees gave much the same reason for their refusal to be promoted over the trees; or, as the margin reads it, to go up and down for the trees. To rule, involves a man in a great deal both of toil and care. Those who are preferred to public trust and power, must forego all private interests and advantages, for the good of others. And those advanced to honour and dignity, are in great danger of losing their fruitfulness. For which reason, they that desire to do good, are afraid of being too great. Jotham compares Abimelech to the bramble or thistle, a worthless plant, whose end is to be burned. Such a one was Abimelech.

Jud 9:7-21. Jotham by a Parable Reproaches Them.

7. he … stood in the top of mount Gerizim and lifted up his voice—The spot he chose was, like the housetops, the public place of Shechem; and the parable [Jud 9:8-15] drawn from the rivalry of the various trees was appropriate to the diversified foliage of the valley below. Eastern people are exceedingly fond of parables and use them for conveying reproofs, which they could not give in any other way. The top of Gerizim is not so high in the rear of the town, as it is nearer to the plain. With a little exertion of voice, he could easily have been heard by the people of the city; for the hill so overhangs the valley, that a person from the side or summit would have no difficulty in speaking to listeners at the base. Modern history records a case, in which soldiers on the hill shouted to the people in the city and endeavored to instigate them to an insurrection. There is something about the elastic atmosphere of an Eastern clime which causes it to transmit sound with wonderful celerity and distinctness [Hackett].