All of God’s prophets have been plain men, like any other.
What distinguished them from others was the divine proof that they brought.
Such divine proofs represent God on earth. To discover God is to see Him in His proofs, such as are evident in creation.
As for those who fail to see Him in His signs, God will disregard them completely on the Day of Resurrection, and they will receive no share in His everlasting blessings.
Only clear minds can recognize clear proofs when shown to them, for only a mind free of all pride and prejudice can see truth in a clear light and accept it. If one rises above worldly attachments, and sees only God as the greatest, then one will have no difficulty realizing the truth of clear proofs.
In this world God comes before one in the form of clear proofs; in the next world He Himself will be plainly visible, in all His glory.
Then, people will have no choice but to believe in Him.
True believers believe in an invisible God, made manifest through His signs in this world, just as others will believe in Him when He becomes visible in the next world.
This is the great test of a person in this world: to believe in a God who is invisible in Himself, but visible through His signs—both in nature and divine revelation.
So categorical and clear are those divine proofs, that one who is sincere in his search for truth cannot fail to recognize them; he will bow before them as if they were God Himself; he will be as certain of their veracity as he would be if God—in all His glory and perfection—were made manifest.