The Statement of Allah: "...And those who hoard up gold and silver (AI-Kanz—the money, the Zakãt of which has not been paid) and spend it not in the Way of Allah—announce to them a painful torment." (V.9:34) Sahih al-Bukhari 4659
Arabic hadith text
حَدَّثَنَا الْحَكَمُ بْنُ نَافِعٍ، أَخْبَرَنَا شُعَيْبٌ، حَدَّثَنَا أَبُو الزِّنَادِ، أَنَّ عَبْدَ الرَّحْمَنِ الأَعْرَجَ، حَدَّثَهُ أَنَّهُ، قَالَ حَدَّثَنِي أَبُو هُرَيْرَةَ ـ رضى الله عنه ـ أَنَّهُ سَمِعَ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ "يَكُونُ كَنْزُ أَحَدِكُمْ يَوْمَ الْقِيَامَةِ شُجَاعًا أَقْرَعَ "
Translation
Narrated Abu Huraira
Allah's Messenger (ﷺ) said, "The Kanz (money, the Zakat of which is not paid) of anyone of you will appear in the form of bald-headed poisonous male snake on the Day of Resurrection."