Does what I promised Allah, to abstain from sins for life in exchange for fulfilling my wish, constitute a vow (nadhr) or an oath (yamin) after my wish was fulfilled and I became unable to fulfill my promise?

It is obligatory to abstain from disobeying Allah absolutely, because the consequences of sins are dire in this world and the hereafter. Allah has warned against resembling the hypocrites who made a covenant with Allah and then were miserly.

As for the questioner's statement: "If you give me such and such, then I will abandon the sin," it is not an oath due to the absence of the oath's formula, and it is not a vow except with the intention. The majority of scholars are of the opinion that a vow to abandon sin is not valid, because it is obligatory by the origin of Islamic law.

Some scholars hold the view that it is a valid vow, so if he commits the sin, he is obligated to offer expiation for an oath. It is preferable not to make the vow the impetus for abandoning the sin, but rather there should be a strong determination to abandon it without a vow.