قَالَ أَبُو عُبَيْدٍ فَنَظَرْتُ فِي حَدِيثِ عُمَرَ هَذَا، فَإِذَا هُوَ قَدْ عَدَلَ أَرْبَعِينَ دِرْهَمًا بِأَرْبَعَةِ دَنَانِيرَ؛ لِأَنَّ أَصْلَ الدَّنَانِيرِ أَنْ يُعْدَلَ الدِّينَارُ بِعَشَرَةِ دَرَاهِمَ
Abu 'Ubayd said When I examined this tradition from 'Umar, I found that he had deemed forty dirhams to be the equivalent of four dinars, because the basic scale for dinars is that they be considered equal to ten dirhams