It is narrated from Sayyiduna Abu Umamah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "The one who gives a guarantee is liable for its payment." Imam al-Muzani (may Allah have mercy on him) said: "Al-za'im" in the language means "al-kafil" (the surety).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحوالة / 11392