What is Salat al-Istikhara, when is it performed, how does the person seeking guidance know what Allah has chosen for him, and does he disobey Allah if he chooses otherwise?

The Istikhara prayer is a recommended act, and the Prophet, peace and blessings be upon him, used to teach it to his companions as he would teach a surah from the Quran. The time for the Istikhara prayer is any time when prayer is permissible, and it should not be performed during times when prayer is prohibited. The goodness of a matter after Istikhara is known either by a feeling of inner peace, or by what the person performing Istikhara decides to do or not to do. There is no sin upon a person for what he decides to do or not to do after performing Istikhara.