Does a debt require a guarantor and two witnesses, and is the debt valid without them?

Guaranteeing and witnessing to document a debt are permissible acts, but they are not pillars or conditions for the validity of the debt itself. Scholars have differed on their ruling. Some view them as not obligatory, but rather for caution, whereas trust is a covenant with God and a sign of honorable conduct from the debtor, as in the hadith of the Children of Israel. The debt is established in the debtor's responsibility between him and God without the need for witness or guarantee. However, in case of dispute, evidence is necessary to prove it, such as testimony or guarantee, based on the Prophet's (peace be upon him) saying: "The burden of proof is on the claimant, and the oath is on the one who denies."