(And as for those who chose) built (a place of worship) the reference here is to 'Abdullah Ibn Ubayy, Jadd Ibn Qays, Mu'attib Ibn Qushayr and their friends, who were about 17 in number, (out of opposition) out of harm for the believers (and disbelief) in their hearts; standing firm in their disbelief, i.e. hypocrisy, (and in order to cause dissent among the believers) such that a party of the believers performed their prayers in their mosque and a party in the Mosque of the Messenger, (and as an outpost) waiting (for those who warred against Allah and His messenger) for those who disbelieved in Allah and his Messenger (aforetime) before them, referring here to Abu 'Amir, the monk, whom the Prophet (pbuh) called a sinner [fasiq], (they will surely swear: We purposed) by building the mosque (naught save good) save good for the believers so that those who miss the prayer in Quba' Mosque can pray therein. (Allah beareth witness) Allah knows (that they verily are liars) in their oaths.
