In the act of retelling the story of his father giving trees to his son, Odysseus rids any of Laertes's doubt and proves he is truly his father's son, who has been gone for twenty long years. Odysseus reuniting with his father is key for solidifying his return home.
"You gave me thireen pear, ten apple trees and forty figs —and promised to give me, look, fifty vinerows.” (24.379-80).