Is it permissible for someone who vowed a prayer rug to a specific mosque to send it with another person, and is the vow still binding if that person does not deliver it?

The vow must be fulfilled because the Prophet, peace be upon him, said: "Whoever vows to obey Allah, let him obey Him..." It is permissible to appoint someone else to deliver the prayer rug to the mosque. The one who made the vow is not absolved until he is certain or predominantly assumes that it has reached its destination. A predominant assumption is sufficient in this regard.