This verse refers to a speech being given by Jotham, the youngest son of Gideon (also called Jerubbaal), to the people of Shechem. He's criticizing them for supporting Abimelech, his half-brother, who has murdered all but one of Gideon's other sons to seize power.

Let's break down the verse:

"(for my father fought for you...": This emphasizes Gideon's (Jotham's father's) previous loyalty and service to the people of Shechem. He wasn't just a random person; he was their leader and protector.

"...and risked his life...": This highlights the personal danger Gideon faced in fighting for them. It wasn't a casual act of service, but a courageous decision to put his own well-being on the line.

"...and delivered you out of the hand of Midian...": This is the key event. Gideon, inspired by God, led a small Israelite force to defeat the much larger and oppressive Midianite army. This brought peace and prosperity to the Israelites, including the people of Shechem.

In essence, the verse is saying: "My father, Gideon, saved you from the Midianites at great personal risk. He gave you freedom and security."

Therefore, the verse serves as a sharp contrast to the actions of the people of Shechem in supporting Abimelech. Jotham is using this historical fact to:

Highlight their ingratitude: They've turned against the house of the man who saved them.
Expose Abimelech's illegitimacy: He's not a worthy successor to Gideon and has gained power through violence, not service.
Foreshadow doom: Jotham's speech is a prophetic curse on both Abimelech and the people of Shechem, warning of the consequences of their treachery and bad decision. His curse later comes true, as both Abimelech and the Shechemites are destroyed.

In short, this verse isn't just about remembering history; it's about highlighting the moral failure of the Shechemites and foreshadowing the tragic consequences of their choices.