Reference: http://www.alfawzan.af.org.sa/node/16197
Question: When he enters the masjid, he prays the [two sunnah] rak’ahs of the fajr [prayer], and combines it with the tahiyyatul-masjid; is that permissible?
Response: Yes [this is permissible], that he prays [the] two rak’ahs [of the fajr prayer] and intends by them [both] the tahiyyatul-masjid and the [two sunnah] rak’ahs of the fajr [prayer]; there is no harm in that. However, if he made the intention to pray the [two sunnah] rak’ahs of the fajr [prayer] – that would suffice him from [praying the two rak’ahs of] tahiyyatul-masjid.
