"Usury" is generally understood to mean "lending money at an interest rate that is considered unreasonably high or that is higher than the rate permitted by law." (source:
What Is Usury? Definition, How It Works, Legality, and Example ).
In the parable of the talents, the master criticized the lazy servant, saying, "Well then, you should have put my money on deposit with the bankers, so that when I returned I would have received it back with interest." (Matthew 25:27). Given this, we cannot conclude that charging
interest is itself wrong. Yes, the borrower is servant to the lender (Proverbs 22:7), but again that is wisdom, not condemnation or commandment.
I encourage you to rethink your position on interest and borrowing. Interest is nothing more than a rightful return on the temporary use of someone else's money. I have no love for high interest on loans, but I recognize that much of the industrial and technological development we enjoy would not exist without interest-bearing loans financing that development.
By the way, if you have any investments (including 401K's or retirement funds) that bear returns other than dividends, you are violating your own principles and are left with no moral ground on which to stand.