Is the employer obliged to pay the wages of a worker who did not commit to completing the agreed-upon work and caused damage to the employer?

The hired worker does not fully deserve his wage unless he completes his work entirely as per the agreement. If his work is not completed, he does not deserve the agreed-upon wage, because he has not fulfilled the contract. Furthermore, his incomplete work might have caused more harm to the employer than if the work had not been started at all.