Sahih al-Bukhari 2429
Narrated Zaid bin Khalid:
A man came and asked Allah's Messenger (ﷺ) about picking a lost thing. The Prophet (ﷺ) said, "Remember the 
description of its container and the string it is tied with, and make public announcement about it for 
one year. If the owner shows up, give it to him; otherwise, do whatever you like with it." He then 
asked, "What about a lost sheep?" The Prophet (ﷺ) said, "It is for you, for your brother (i.e. its owner), or 
for the wolf." He further asked, "What about a lost camel?" The Prophet (ﷺ) said, "It is none of your 
concern. It has its water-container (reservoir) and its feet, and it will reach water and drink it and eat 
the trees till its owner finds it."
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يُوسُفَ، أَخْبَرَنَا مَالِكٌ، عَنْ رَبِيعَةَ بْنِ أَبِي عَبْدِ الرَّحْمَنِ، عَنْ يَزِيدَ، مَوْلَى الْمُنْبَعِثِ عَنْ زَيْدِ بْنِ خَالِدٍ ـ رضى الله عنه ـ قَالَ جَاءَ رَجُلٌ إِلَى رَسُولِ اللَّهِ صلى الله عليه وسلم فَسَأَلَهُ عَنِ اللُّقَطَةِ‏.‏ فَقَالَ ‏"‏ اعْرِفْ عِفَاصَهَا وَوِكَاءَهَا، ثُمَّ عَرِّفْهَا سَنَةً، فَإِنْ جَاءَ صَاحِبُهَا، وَإِلاَّ فَشَأْنَكَ بِهَا ‏"‏‏.‏ قَالَ فَضَالَّةُ الْغَنَمِ قَالَ ‏"‏ هِيَ لَكَ أَوْ لأَخِيكَ أَوْ لِلذِّئْبِ ‏"‏‏.‏ قَالَ فَضَالَّةُ الإِبِلِ قَالَ ‏"‏ مَا لَكَ وَلَهَا، مَعَهَا سِقَاؤُهَا وَحِذَاؤُهَا، تَرِدُ الْمَاءَ وَتَأْكُلُ الشَّجَرَ، حَتَّى يَلْقَاهَا رَبُّهَا ‏"‏‏.‏