Sahih Muslim Book 37, Hadith Number 6617.

Chapter : Exhortation for repentance.

Al-Bara’ b. ‘Azib reported Allah’s Messenger (may peace be upon him) as saying that Allah’s Messenger (may peace be upon him) said: What is your opinion about the delight of a person whose camel loaded with the provisions of food and drink is lost and that moves about with its nose-string trailing upon the waterless desert in which there is neither food nor drink, and lie wanders about in search of that until he is completely exhausted and then accidentally it happens to pass by the trunk of a tree and its nose-string gets entangled in that and he finds it entangled therein? He (in response to the question of the Holy Prophet) said: Allah’s Messenger, he would feel highly delighted. Thereupon Allah’s Messenger (may peace be upon him) said. By Allah, Allah is more delighted at the repentance of His servant than that person (as he finds his lost) camel.