We went out with 'Abdullah bin 'Umar and a bedouin said (to 'Abdullah), "Tell me about Allah's saying: "And those who hoard up gold and silver (Al-Kanz - money, gold, silver etc., the Zakat of which has not been paid) and spend it not in the Way of Allah (V.9:34)." Ibn 'Umar said, "Whoever hoarded them and did not pay the Zakat thereof, then woe to him. But these holy Verses were revealed before the Verses of Zakat. So when the Verses of Zakat were revealed, Allah made Zakat a purifier of the property."  

أَخْبِرْنِي قَوْلَ اللَّهِ {وَالَّذِينَ يَكْنِزُونَ الذَّهَبَ وَالْفِضَّةَ وَلاَ يُنْفِقُونَهَا فِي سَبِيلِ اللَّهِ} قَالَ ابْنُ عُمَرَ ؓ مَنْ كَنَزَهَا فَلَمْ يُؤَدِّ زَكَاتَهَا فَوَيْلٌ لَهُ إِنَّمَا كَانَ هَذَا قَبْلَ أَنْ تُنْزَلَ الزَّكَاةُ فَلَمَّا أُنْزِلَتْ جَعَلَهَا اللَّهُ طُهْرًا لِلأَمْوَالِ  

[Machine] The Bedouin says "Allah says: {And those who accumulate gold and silver} [Al-Tawbah 34]." Ibn Umar said, "Whoever hoards them and does not pay their zakat (charitable alms), may he be doomed. This was only before the zakat was revealed. When it was revealed, Allah made it a purification for wealth." Then he turned to me and said, "I do not care if I had as much gold as Mount Uhud, I would know its amount, purify it, and spend in obedience to Allah."  

الْأَعْرَابِيُّ يَقُولُ اللهُ ﷻ {وَالَّذِينَ يَكْنِزُونَ الذَّهَبَ وَالْفِضَّةَ} [التوبة 34] فَقَالَ ابْنُ عُمَرَ مَنْ كَنَزَهُمَا وَلَمْ يُؤَدِّ زَكَاتَهُمَا فَوَيْلٌ لَهُ إِنَّمَا كَانَ هَذَا قَبْلَ أَنْ تَنْزِلَ الزَّكَاةُ فَلَمَّا نَزَلَتْ جَعَلَهَا اللهُ طُهْرَةً لِلْأَمْوَالِ ثُمَّ الْتَفَتَ إِلَيَّ فَقَالَ مَا أُبَالِي لَوْ كَانَ لِي مِثْلُ أُحُدٍ ذَهَبًا أَعْلَمُ عَدَدَهُ وَأُزَكِّيهِ وَأَعْمَلُ فِيهِ بِطَاعَةِ اللهِ ﷻ