مُوَطَّأُ مَالِكٍ
Muwatta Malik 608
Zakat
حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّ أَبَا بَكْرٍ الصِّدِّيقَ، قَالَ لَوْ مَنَعُونِي عِقَالاً لَجَاهَدْتُهُمْ عَلَيْهِ .
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."
Arabic/English book reference: Book 17, Hadith 31