Overall meaning : It is Allah who has sent down tranquillity into the hearts of the believers among the Companions of His Prophet when the Quraysh unbelievers prevented them from entering the Sacred Mosque in Makkah in the year Al-Hudaybiyyah peace treaty was signed, so that they might have more faith added to their faith. To Allah alone belong all the forces of the heavens and the earth (the forces of the angels, the jinn and humans, among others). Allah is indeed All-Knowing, All-Wise.
He did this so that He might admit the believing men and women into gardens beneath which rivers flow to dwell there for ever, and forgive them their sins. Such a promise is, in Allah’s sight, a supreme triumph indeed. He also did this so that He might punish, in this world, the male and female hypocrites and idolaters, who entertain the evil thought that Allah will not grant victory to His Messenger and the believers and make his religion prevail over unbelief and its advocates. They will suffer an evil turn of fate, which will encompass them from all sides. Allah is angry with them; He has expelled them from His mercy and prepared Hell for them in the hereafter—an evil destination indeed!
To Allah alone belong all the forces of the heavens and the earth. Allah is the All-Mighty who holds sway over all things, the All-Wise who puts everything in its perfect place.