the general wording of, “There is no prayer after the dawn prayer,” or, “after the afternoon prayer,” while not relying on the general wording of, “When any one of you enters the mosque, let him not sit until he has prayed two rak‘ahs.”
Third: such prayers are connected to a particular cause, so it is unlikely that they could be confused with imitating the polytheists. Prayer before sunrise and before sunset was prohibited lest the Muslim worshipper resemble the polytheists who prostrate to the sun when it rises and when it sets. But when the prayer is occasioned by a known cause, such resemblance is remote or nonexistent.
Fourth: one wording of the hadiths prohibiting prayer states: “Do not deliberately seek out sunrise or sunset for your prayers” (1). A person who prays for a particular reason cannot be described as deliberately seeking it out; rather, it is said that he prayed due to that reason.
The one who deliberately seeks it out is the person who watches the sun and, when it draws near to rising, for example, stands and prays; or the one who watches for the prohibited time and, when it arrives, stands and prays. This is the view of al-Shafi‘i, one of the two narrations from Imam Ahmad, may Allah have mercy on him, and the preferred view of Shaykh al-Islam Ibn Taymiyyah, our teacher Abd al-Rahman ibn Sa‘di, and our teacher Abd al-Aziz ibn Baz.
Accordingly, if you enter the mosque for the Maghrib prayer, for example, a quarter of an hour before sunset, you should pray, and there is no harm in doing so. Indeed, if you were to sit down, you would be falling into what the Messenger of Allah, peace and blessings be upon him, prohibited for one who enters the mosque: sitting before praying two rak‘ahs.