'Umar (ra) sent him (i.e. Hamza) as a Sadaqa / Zakat collector. A man had committed illegal sexual intercourse with the slave girl of his wife. Hamza took (personal) sureties for the adulterer till they came to 'Umar. 'Umar had lashed the adulterer one hundred lashes. 'Umar confirmed their claim (that the adulterer had already been punished) and excused him because of being Ignorant. Jarir Al-Ash'ath said to Ibn Mas'ud regarding renegades (i.e., those who became infidels after embracing Islam), "Let them repent and take (personal) sureties for them." They repented and their relatives stood sureties for them. According to Hammad, if somebody stands surety for another person and that person dies, the person giving surety will be released from responsibility. According to Al-Hakam, his responsibilities continues.  

أَنَّ عُمَرَ ؓ بَعَثَهُ مُصَدِّقًا فَوَقَعَ رَجُلٌ عَلَى جَارِيَةِ امْرَأَتِهِ فَأَخَذَ حَمْزَةُ مِنَ الرَّجُلِ كَفِيلاً حَتَّى قَدِمَ عَلَى عُمَرَ وَكَانَ عُمَرُ قَدْ جَلَدَهُ مِائَةَ جَلْدَةٍ فَصَدَّقَهُمْ وَعَذَرَهُ بِالْجَهَالَةِ وَقَالَ جَرِيرٌ وَالأَشْعَثُ لِعَبْدِ اللَّهِ بْنِ مَسْعُودٍ فِي الْمُرْتَدِّينَ اسْتَتِبْهُمْ وَكَفِّلْهُمْ فَتَابُوا وَكَفَلَهُمْ عَشَائِرُهُمْ وَقَالَ حَمَّادٌ إِذَا تَكَفَّلَ بِنَفْسٍ فَمَاتَ فَلاَ شَىْءَ عَلَيْهِ وَقَالَ الْحَكَمُ يَضْمَنُ