Source : Qibla.com / 31 Mar 2014

Question :

If someone enters the mosque while the call to prayer is being given, then should he remain standing and repeat the words of the call to prayer and then pray the rak‘as of greeting the mosque after the call to prayer is completed? Or should he pray the rak‘as of greeting the mosque first and then repeat whatever words of the call to prayer that he is able to (if anything of it remains) after his salams [h: upon completing his prayer]? Or is there even any preference?

Answer :

بسم الله الرحمن الرحيم الحمدلله رب العالمين وصلى الله على سيدنا محمد و على آله و صحبه و سلم أما بعد

It is best for him to remain standing and repeat the call to prayer and then pray the rak‘as of greeting the mosque.