Sahih Muslim Book - 37, Hadith - 5478

حَدَّثَنَا يَحْيَى بْنُ يَحْيَى وَخَلَفُ بْنُ هِشَامٍ وَأَبُو الرَّبِيعِ الْعَتَكِيُّ كُلُّهُمْ عَنْ حَمَّادٍ قَالَ يَحْيَى أَخْبَرَنَا حَمَّادُ بْنُ زَيْدٍ عَنْ عَبْدِ الْعَزِيزِ بْنِ صُهَيْبٍ عَنْ أَنَسِ بْنِ مَالِكٍ أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ اتَّخَذَ خَاتَمًا مِنْ فِضَّةٍ وَنَقَشَ فِيهِ مُحَمَّدٌ رَسُولُ اللَّهِ وَقَالَ لِلنَّاسِ: إِنِّي اتَّخَذْتُ خَاتَمًا مِنْ فِضَّةٍ وَنَقَشْتُ فِيهِ مُحَمَّدٌ رَسُولُ اللَّهِ فَلَا يَنْقُشْ أَحَدٌ عَلَى نَقْشِهِ.

It was narrated from Anas bin Malik that the Prophet (s.a.w) acquired a ring of silver, on which was engraved 'Muhammad Rasul Allah', and he said to the people: "I have acquired a ring of silver and engraved on it 'Muhammad Rasul Allah,' and no one should have an engraving like this."