Answer:

It seems you are mixing various ideas to create a falsehood.

In the Old Testament, it was wrong for an Israelite to charge interest on a loan to another Israelite who is poor.

"If you lend money to My people, to the poor among you, you are not to act as a creditor to him; you shall not charge him interest" (Exodus 22:25).

"Now in case a countryman of yours becomes poor and his means with regard to you falter, then you are to sustain him, like a stranger or a sojourner, that he may live with you. Do not take usurious interest from him, but revere your God, that your countryman may live with you. You shall not give him your silver at interest, nor your food for gain" (Leviticus 25:35-37).

Loaning money was allowed, but there were rules that required the lender to treat those who owed money with respect. "When you make your neighbor a loan of any sort, you shall not enter his house to take his pledge. You shall remain outside, and the man to whom you make the loan shall bring the pledge out to you" (Deuteronomy 24:10-11).

Taking out a Fixed Deposit at a bank is a transaction where you loan your money to the bank and, in exchange, the bank pays the principal and a fixed percentage back to you at a predefined time. This isn't what the Old Testament laws were discussing. Such loans were not forbidden. As you noted, Jesus used the depositing of money in a bank in one of his parables, showing that it was a normal part of society. "Then you ought to have put my money in the bank, and on my arrival I would have received my money back with interest" (Matthew 25:27).