Yahya related to me from Malik that he had heard that Abu Bakr as-Siddiq said, "If they withhold even a hobbling cord I will fight them over it."  

أَنَّ أَبَا بَكْرٍ الصِّدِّيقَ قَالَ لَوْ مَنَعُونِي عِقَالاً لَجَاهَدْتُهُمْ عَلَيْهِ  

Yahya related to me from Malik that Zayd ibn Aslam said, ''Umar ibn al Khattab drank some milk which he liked (very much) and he asked the man who had given it to him, 'Where did this milk come from?' The man told him that he had come to a watering-place, which he named, and had found grazing livestock from the zakat watering there. He was given some of their milk, which he then put into his water-skin, and that was the milk in question. Umar ibn al-Khattab then put his hand into his mouth to make himself vomit." Malik said, "The position with us is that if anyone refuses to honour one of the obligatory demands of Allah, and the muslims are unable to get it, then they have the right to fight him until they get itfrom him."  

أَنَّهُ قَالَ شَرِبَ عُمَرُ بْنُ الْخَطَّابِ لَبَنًا فَأَعْجَبَهُ فَسَأَلَ الَّذِي سَقَاهُ مِنْ أَيْنَ هَذَا اللَّبَنُ فَأَخْبَرَهُ أَنَّهُ وَرَدَ عَلَى مَاءٍ قَدْ سَمَّاهُ فَإِذَا نَعَمٌ مِنْ نَعَمِ الصَّدَقَةِ وَهُمْ يَسْقُونَ فَحَلَبُوا لِي مِنْ أَلْبَانِهَا فَجَعَلْتُهُ فِي سِقَائِي فَهُوَ هَذَا فَأَدْخَلَ عُمَرُ بْنُ الْخَطَّابِ يَدَهُ فَاسْتَقَاءَهُ قَالَ مَالِكٌ الأَمْرُ عِنْدَنَا أَنَّ كُلَّ مَنْ مَنَعَ فَرِيضَةً مِنْ فَرَائِضِ اللَّهِ ﷻ فَلَمْ يَسْتَطِعِ الْمُسْلِمُونَ أَخْذَهَا كَانَ حَقًّا عَلَيْهِمْ جِهَادُهُ حَتَّى يَأْخُذُوهَا مِنْهُ  

Yahya related to me from Malik that he had heard that one of the administrators of Umar ibn Abd al-'Aziz wrote to him mentioning that a man had refused to pay zakat on his property. Umar wrote to the administrator and told him to leave the man alone and not to take any zakat from him when he took it from the other muslims. The man heard about this and the situation became unbearable for him, and after that he paid the zakat on his property. The administrator wrote to Umar and mentioned that to him, and Umar wrote back telling him to take the zakat from him.  

أَنَّ عَامِلاً لِعُمَرَ بْنِ عَبْدِ الْعَزِيزِ كَتَبَ إِلَيْهِ يَذْكُرُ أَنَّ رَجُلاً مَنَعَ زَكَاةَ مَالِهِ فَكَتَبَ إِلَيْهِ عُمَرُ أَنْ دَعْهُ وَلاَ تَأْخُذْ مِنْهُ زَكَاةً مَعَ الْمُسْلِمِينَ قَالَ فَبَلَغَ ذَلِكَ الرَّجُلَ فَاشْتَدَّ عَلَيْهِ وَأَدَّى بَعْدَ ذَلِكَ زَكَاةَ مَالِهِ فَكَتَبَ عَامِلُ عُمَرَ إِلَيْهِ يَذْكُرُ لَهُ ذَلِكَ فَكَتَبَ إِلَيْهِ عُمَرُ أَنْ خُذْهَا مِنْهُ