In the Quran," Who is he that will loan to Allah a beautiful loan, which Allah will double unto his credit and multiply many times? .........." mentioned in various ayats, what does this ayat truly mean? It has been, sited in the Bible also, (but no longer remains)
Assalamou alaikum dear sister,
this verse/ayat means that whoever spend from his/her money in the path of Allah(to his family, poor, needy...etc.) is like giving loan to Allah, and in the day of Judgment he/she will be rewarded for it multiplied many times.
"And why do you not spend in the cause of Allāh while to Allāh belongs the heritage of the heavens and the earth? Not equal among you are those who spent before the conquest [of Makkah] and fought [and those who did so after it]. Those are greater in degree than they who spent afterwards and fought. But to all Allāh has promised the best [reward]. And Allāh, with what you do, is Acquainted. Who is it that would loan Allāh a goodly loan so He will multiply it for him and he will have a noble reward?" (57:10-11)
"Who is it that would loan Allāh a goodly loan so He may multiply it for him many times over? And it is Allāh who withholds and grants abundance, and to Him you will be returned."(2:245)
It is like when we be a reason/bridge for that the good of Allah reach the others is like giving loan to Allah for that the good/money/help/efforts will benefit the others. actually the money belongs to Allah, and it is His character that He grasp/withhold(al qabed) and the spender/spreader/grant abundance(al basit).. and when someone spend on the cause of Allah is the manifestation of the name of Allah el basit.. and when someone withhold is the manifestation of the name of Allah el qabed.. and successful is the person that Allah let him/her be a reason of driving the good of Allah to others. as sayidna Muhammad sala Allahou alyhi wa sallam was described as "mercy to the worlds" while the mercy is all from and belong to Allah alone.. but because he was a reason of driving Allah's mercy to the worlds then he himself was called "a mercy to the worlds".
and regarding the reward for the one who spend in Allah's path/cause(giving loan to Allah) is multiplied many many times when we return to Him. "The example of those who spend their wealth in the way of Allāh is like a seed [of grain] which grows seven spikes; in each spike is a hundred grains. And Allāh multiplies [His reward] for whom He wills. And Allāh is all-Encompassing and Knowing. Those who spend their wealth in the way of Allāh and then do not follow up what they have spent with reminders [of it] or [other] injury will have their reward with their Lord, and there will be no fear concerning them, nor will they grieve. Kind speech and forgiveness are better than charity followed by injury. And Allāh is Free of need and Forbearing. O you who have believed, do not invalidate your charities with reminders or injury as does one who spends his wealth [only] to be seen by the people and does not believe in Allāh and the Last Day. His example is like that of a [large] smooth stone upon which is dust and is hit by a downpour that leaves it bare. They are unable [to keep] anything of what they have earned. And Allāh does not guide the disbelieving people. And the example of those who spend their wealth seeking means to the approval of Allāh and assuring [reward for] themselves is like a garden on high ground which is hit by a downpour – so it yields its fruits in double. And [even] if it is not hit by a downpour, then a drizzle [is sufficient]. And Allāh, of what you do, is Seeing. Would one of you like to have a garden of palm trees and grapevines underneath which rivers flow in which he has from every fruit? But he is afflicted with old age and has weak offspring, and it is hit by a whirlwind containing fire and is burned. Thus does Allāh make clear to you [His] verses that you might give thought. O you who have believed, spend from the good things which you have earned and from that which We have produced for you from the earth. And do not aim toward the defective therefrom, spending [from that] while you would not take it [yourself] except with closed eyes. And know that Allāh is Free of need and Praiseworthy. Satan threatens you with poverty and orders you to immorality, while Allāh promises you forgiveness from Him and bounty. And Allāh is all-Encompassing and Knowing." (2:261-268)
and Allah knows better