What is the story of Prophet Mūsā (peace be upon him) with the man who took him, then they went to the ship and later encountered the boy—and was that man an angel or from the jinn?

The story of Moses and Al-Khidr (peace be upon them both) begins when Moses (peace be upon him) was asked who was the most knowledgeable among people, and he thought it was himself. So, Allah admonished him and revealed to him that there was a servant more knowledgeable than him at the confluence of the two seas. Moses set off with his young companion, Joshua son of Nun (peace be upon them both), to that place. The sign of arrival was the loss of the fish they were carrying. When they forgot the fish, they passed the place. Moses then felt tired, and when his companion reminded him about the fish, Moses returned to the spot where it was lost, and there they met Al-Khidr. Moses asked to follow him to learn from him, and Al-Khidr agreed on the condition that Moses would not question him about anything until Al-Khidr himself explained it.

Al-Khidr performed three strange actions that Moses could not bear: 1. Piercing the boat: When they boarded a boat, its owners recognized them and carried them without fare. Al-Khidr then proceeded to pierce the boat. 2. Killing the boy: After disembarking from the boat, Al-Khidr saw a boy and killed him. 3. Restoring the wall: They arrived at a stingy village whose inhabitants refused to host them. They found a wall on the verge of collapsing, and Al-Khidr restored it without asking for payment.

After each action, Moses would ask Al-Khidr for the reason, and Al-Khidr would remind him of the need for patience. After the third time, Al-Khidr explained to Moses the interpretation of his actions: 1. Piercing the boat: To protect it from a tyrannical king who would seize every sound boat. 2. Killing the boy: Because he would have grown up to be an disbeliever and oppressive towards his believing parents, so Allah willed to replace him with someone better for them. 3. Restoring the wall: Because it belonged to two righteous orphaned boys, and there was a treasure beneath it for them. Allah willed for them to reach maturity and extract their treasure.

Al-Khidr clarified that what he did was not of his own accord, but by the command of Allah.