The ruling on one who bought a commodity and had a balance remaining from what he paid

Question:
A man wanted to buy a need from a shop. He had only one hundred riyals with him. He bought a need for fifty riyals, and fifty remained. The balance was not present with the shop owner...?

Answer:
He should give him a delay, or else leave the hundred with him as a trust until he brings the fifty. Or else, he gives it to him and returns fifty to him. The matter is broad. Either he gives it to him and returns fifty to him, or he gives him a delay and grants him time until he brings the fifty, or he leaves it with him as a trust until he brings the fifty, like a pledge.