The answer
Vows are a rare form of worship. There are several vows one makes throughout his/her life: marriage, monasticism, consecration, baptism of a child, a particular petition, etc. Unfortunately, sometimes people forget that their marriages and the baptism of their children are indeed vows of which they will be held accountable.
There are some vows to which one adds a condition. Nonetheless, it should not mean that it is 'this for that'. One should perform the vow at least once regardless of the outcome. These kinds of vows are presented as deep prayers beseeching God for a specific petition. One promises to dedicate time, talent, or treasure as an offering, but not as compensation. How can anyone ever compensate God for anything?
God teaches us to be people of our word, to keep our promises to each other and to God. When Zacchaeus the chief tax collector repented, Christ forgave him and did not request anything more of him (Luke 19:1-10). Yet, Zacchaeus was overwhelmed by God's generous mercies and vowed to give back what he felt he owed and more as proof of his seriousness and true repentance.
Answered by His Eminence Metropolitan Youssef (opens in a new tab)