What is the ruling on someone who utters a vow without completing it, such such as saying: "I promise You, O Lord, that I will not drink alcoho—" and does not complete "alcohol"?

A Muslim is obliged to abstain from alcohol and all other forbidden things. His promise to his Lord to abandon sins only adds emphasis, especially since alcohol is the mother of all evils that Allah has commanded us to avoid, as He says: "O you who have believed, indeed intoxicants, gambling, [sacrificing to] stone altars for idols, and divining arrows are but defilement from the work of Satan, so avoid it that you may be successful. Satan only wants to cause animosity and hatred between you through intoxicants and gambling and to avert you from the remembrance of Allah and from prayer. So will you not desist?"