Is it permissible to select specific verses from the Qur’an and designate them for particular ailments by way of Ruqyah, such as saying: “For every tiding there is a set time” for headaches, and “Then He sent down upon you, after the distress, security, slumber” for insomnia?

The Holy Qur’an is a healing and a mercy for believers from all ailments. It is legislated to ask Allah by it and to perform Ruqyah with it. It is stated in the Hadith: “Recite the Qur’an and ask Allah by it.” It is a healing for what is in the chests and a guidance for the believers. And whoever is not healed by the Qur’an, may Allah not heal him. There is no harm in reciting a verse or verses to treat a specific illness, and it is better to regularly recite the Qur’an and supplicate after the recitation with anything from the Qur’an.