Liability reduces profit?

Take this example of a salary entry for March.

Salary a/c (provision for march) Dr.
To Salary Payable (liability) Cr.

You created both provision and liability. Only liability cannot be created. Something has to be debited i.e either provision or expense in P&L account.

If the payment is made, there is no liability, in place of liability bank account is credited.

Hope this is what you wanted to clarify.