Guidance is the hands of Allah
Guidance is in the hand of Allah. If Allah willed, He could guide all of mankind, for there is nothing that He cannot do on this earth or in the heavens. Nothing happens in His Dominion except that which He wills.
“Say: ‘With Allah is the perfect proof and argument, (i.e. the Oneness of Allah, the sending of His Messengers and His Holy Books, to mankind); had He so willed, He would indeed have guided you all.’”
[al-An’am 6:149 – interpretation of the meaning]
But in His Wisdom, Allah has created us with the ability to choose, and He has sent down to us guidance and the Criterion. So whoever obeys Allah and His Messenger will enter Paradise and whoever disobeys Allah and His Messenger will enter Hell, as Allah says (interpretation of the meaning):
“Verily, proofs have come to you from your Lord, so whosoever sees, will do so for (the good of) his ownself, and whosoever blinds himself, will do so to his own harm, and I (Muhammad) am not a watcher over you.”