عَنْ أَنَسِ بْنِ مَالِكٍ رَضِيَ اللَّهُ عَنْهُ فِي كِتَابِ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ الَّذِي جَمَعَ فِيهِ فَرَائِضَ الصَّدَقَةِ، قَالَ: ((وَفِي الرِّقَاقِ رُبُعُ الْعُشُورِ، فَإِذَا لَمْ يَكُنِ الْمَالُ إِلَّا تِسْعِينَ وَمِائَةَ دِرْهَمٍ فَلَيْسَ فِيهَا شَيْءٌ إِلَّا أَنْ يَشَاءَ رَبُّهَا))
It is narrated from Sayyiduna Anas bin Malik, may Allah be pleased with him, that in the written document of the Messenger of Allah, peace and blessings be upon him, which contained the rules of Zakat, it was also stated: One-fortieth part is obligatory as Zakat on silver. If the amount of silver is one hundred and ninety dirhams, then Zakat is not obligatory on it, but if its owner wishes, then it is permissible.