Who is more unjust that those (the idol worshippers of Mecca) who prevent the believers to mention the name of God in places devoted to His worship (like in Mecca which is built by Abraham for the purpose of worshipping the Lord.) such people do not deserve to enter there. If they enter there at all, they should not feel safe. There is nothing but misery for them in this world and an awful punishment is waiting for them in the Hereafter.