If a person performs the supererogatory Salah (prayer) done before the Fajr (Dawn) Prayer at home, then he goes to the Masjid (mosque), should he perform Tahiyyat-ul-Masjid (two-unit Prayer to salute the mosque) upon entering it?
What is the evidence for this?
If you perform the supererogatory Salah done before Fajr Prayer at home then come to the Masjid, you are allowed to perform Tahiyyat-ul-Masjid. This is proven by the general meaning of the saying of the Prophet (peace be upon him):
"When anyone of you enters the Masjid, he should not sit till he observes two Rak`ahs."
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.