The Quran

۞ يا أَيُّهَا الَّذينَ آمَنوا إِنَّ كَثيرًا مِنَ الأَحبارِ وَالرُّهبانِ لَيَأكُلونَ أَموالَ النّاسِ بِالباطِلِ وَيَصُدّونَ عَن سَبيلِ اللَّهِ ۗ وَالَّذينَ يَكنِزونَ الذَّهَبَ وَالفِضَّةَ وَلا يُنفِقونَها في سَبيلِ اللَّهِ فَبَشِّرهُم بِعَذابٍ أَليمٍ

Muhammad Asad

O you who have attained to faith! Behold, many of the rabbis and monks do indeed wrongfully devour men's possessions and turn [others] away from the path of God. But as for all who lay up treasures of gold and silver and do not spend them for the sake of God¹ - give them the tiding of grievous suffering [in the life to come]:

Most probably this is, in the first instance, an allusion to the wealth of the Jewish and Christian communities, and their misuse of this wealth. Some of the commentators, however, are of the opinion that the reference is wider, comprising all people, including Muslims, who hoard their wealth without spending anything thereof on righteous causes.