Interest and Credit- Human Needs and Economic activities

I have no idea and often trapped into the question of justice whenever the interest is in question. A poor can get no credit i.e. indeterminate discount has been applied to the credit and rich gets the cheapest credit. Poor seems to need it the most yet he/she can't score it. Middle class gets it with high interest rates and more than sufficient collateral held. While rich can get it without or very little of his/her own asset. 

Satapath Brahaman and Manu Smriti clearly allowed taking interest within certain limits and certain law. Little bit of finance and little bit of economics in my head seems to agree that the interest is the must on credit and poorer the quality of credit higher the interest rate must be. Why? Interest is the return and this includes premium for risk taken. Poor quality credit has higher chance of defaulting and thus the premium will be higher. 

What about the poor that is in need of money? First the principal and then the added higher rate of interest.  That person could never seem to trade the path to repay that credit. Except for health and other emergency such as education (education is the emergency or the bar created by rich on poor to make them poor forever (sometimes I fee nothing less than that haha)), credit limits the non-productive uses of fund such as dowry, gambling etc. Some third class lender however from ages had lent to eat out the wealth of others for such useless purposes. they are nothing less than human form of monsters. 

The role of interest to protect the right uses of credit and the limiting the lives at time of emergency seems to be two end of the rope. Can we make a circle and reconcile the problem?

May be the interest rate as a barometer should be limited to productive sector alone. In a pure economic activities. 

While for humanitarian crisis there should be a fund as a charity without need to repay any interest and if the purpose of the fund could not be met such as saving a life, the principal too should not be repaid. There must be a charity bank, where a men of good heart and great deeds keep fund, which the person in need can access (surely not feasible for a country of frauds where even jobs can't be earned by virtue of merit) the fund to the extent of need without any interest. 

Interest is perfectly a fine tool for preventing misuses of loan or to secure the income earned and to protect the seed of capital in economic activities.

And it should be limited only to the area of economics activities or activities to earn something. And the charity bank though should be involved in economics activities to preserve the capital.

xyz------lack of knowledge-----