Is it permissible to save an amount of money to pay quarterly bills to avoid the accumulation of debts and the need to borrow, while relying on Allah?

There is no harm in keeping money and not spending it on bills or other things, provided that the obligatory rights are fulfilled, such as Zakat and spending on those whose maintenance is obligatory. The money must not be placed in an interest-bearing bank, and it is not permissible to take interest on it. However, it is permissible to place it in an Islamic bank that adheres to Sharia-compliant conditions.