Why is charity referred to as a loan?

Imām Ibn al-Jawzī (d. 597/1201) summarized the scholars' opinions in his book "Zād al-Masīr" as follows:

If it is asked why charity is referred to as a "loan," there are three explanations:

1. Because this "loan" is given in exchange for a reward.
2. Because its repayment is delayed until the Day of Judgement.
3. To emphasise that the giver is entitled to reward, as a loan always necessitates a due compensation.