If a person makes a vow and says, “If Allah heals my sick person, I will fast ten days in Rajab every year,” does he have to fulfill his vow?

Question:
May Allah reward you, Honorable Shaykh. This questioner says: If a person makes a vow and says, “If Allah heals my sick person, I will fast ten days in Rajab every year,” does he have to fulfill his vow by fasting ten days in Rajab, given that some people hold Rajab in high regard?

Answer:
This is a disliked vow, because singling out Rajab for worship, to the exclusion of other times, is a disliked vow. Therefore, he does not fulfill it. This is not a vow of obedience; it is singling out Rajab. So he fasts the ten days in a month other than Rajab. Yes.