Abu Dawud Book 14, Hadith Number 3083.
Narated By Amir ar-Ram : We were in our country when flags and banners were raised. I said: What is this?
The (the people) said: This is the banner of the Apostle of Allah (PBUH). So I came to him. He was (sitting) under a tree. A sheet of cloth was spread for him and he was sitting on it. His Companions were gathered around him. I sat with them.
The Apostle of Allah (PBUH) mentioned illness and said: When a believer is afflicted by illness and Allah cures him of it, it serves as an atonement for his previous sins and a warning to him for the future.
But when a hypocrite becomes ill and is then cured, he is like a camel which has been tethered and then let loose by its owners, but does not know why they tethered it and why they let it loose.
A man from among those around him asked: Apostle of Allah, what are illnesses? I swear by Allah, I never fell ill.
The Apostle of Allah (PBUH) said: Get up and leave us. You do not belong to our number. When we were with him, a man came to him. He had a sheet of cloth and something in his hand.
He turned his attention to him and said: Apostle of Allah, when I saw you, I turned towards you. I saw a group of trees and heard the sound of fledglings. I took them and put them in my garment. Their mother then came and began to hover round my head. I showed them to her, and she fell on them. I wrapped them with my garment. They are now with me.
He said: Put them away from you. So I put them away, but their mother stayed with them.
The Apostle of Allah (PBUH) said to his companions: Are you surprised at the affection of the mother for her young?
They said: Yes, Apostle of Allah. He said: I swear by Him Who has sent me with the Truth, Allah is more affectionate to His servants than a mother to her young ones. Take them back put them and where you took them from when their mother should have been with them. So he took them back.