Is not marrying throughout one's life, for both the one who is able and the one who is unable to do so, considered haram and a deviation from the Sunnah of the Prophet Muhammad, peace and blessings be upon him, bearing in mind that Imam Ibn Taymiyyah, Al-Tabari, and Al-Nawawi did not marry? And does a person have complete freedom regarding whether or not to marry, whether they are able or not, and what does "ability" mean?

The Sharia encourages marriage, and it is not absolutely forbidden. Its ruling varies according to circumstances, ranging from obligatory to recommended, permissible, disliked, or forbidden. One who is capable of marriage should not abandon it, due to the religious and worldly benefits they would miss. Some scholars refrained from marriage, and this is interpreted in the best possible light, as they had a valid purpose for doing so.