A shepherd, who feeds and protects his sheep, is a metaphor for the ruler, who will provide for and protect the people of Israel. AT: "Yahweh will give him the strength to lead his people" (See: [[rc://en/ta/man/translate/figs-metaphor]])
The person's name is a metonym for person's authority. AT: "and people will honor him because Yahweh his God has given him the authority to rule" (See: [[rc://en/ta/man/translate/figs-metonymy]])
Here "shepherds" is a metonym for "rulers," another way of saying "leaders over men." The phrase "seven ... and eight" is an idiom for "more than enough." AT: "enough, even more than enough, rulers" or "more than enough shepherds and leaders over men" (See: [[rc://en/ta/man/translate/figs-metaphor]] and [[rc://en/ta/man/translate/figs-idiom]])