Overall meaning :
The desert Arabs into whose hearts faith has not yet entered say to you, Muhammad, ‘We wholeheartedly believe what you have brought us.’ Say to them, ‘You have not attained perfect faith yet. You should rather say, “We have outwardly submitted ourselves to Allah,” for faith has not yet found its way into your hearts. If you obey Allah and His Messenger, He will by no means deny you the reward of your good deeds. Surely Allah is All-Forgiving, All-Merciful.’
The true believers are those who sincerely believe in Allah and His Messenger and never entertain any doubts about this afterwards, and who strive hard in Allah’s cause with their possessions and their lives. These are they who are true believers.
Say to these desert Arabs, ‘Do you presume to inform Allah about your religion, when Allah knows all that is in the heavens and the earth? Nothing whatsoever is hidden from Him and you need not inform Him of the inner secrets of your hearts; for Allah has full knowledge of all things.’
These desert Arabs think they have done you a favour, Muhammad, by embracing Islam. Say to them, ‘You have done me no favour at all by your accepting Islam. It is indeed Allah who has bestowed a favour on you by guiding you to the true faith. Admit this, if you are telling the truth.’
Allah knows all that is hidden in the heavens and the earth. Allah is fully aware of everything you do.