Imamsheds light on the subject as following:
It is possible that one can logically prove the existence of the Great Intelligent Designer, the Unity of His Divine Being, the Day of Judgment and other true beliefs, but such a belief cannot be considered as faith (iman), and the person cannot be regarded as a mu’min, but he may be counted among the non-believers, hypocrites and polytheists.
Today my eyes and yours are closed, and we do not possess any divine vision. Our terrestrial eyes are unable to perceive, but when the hidden is revealed and the kingdom of heaven is manifested, the physical world vanishes and reality is disclosed; you will realize that you were not a believer in God, and your rational judgment was not congruous with your faith.
Unless the words, —there is no god except God— are inscribed on the tablet of the heart with the pen of reason, man is not a true believer in the Unity of God.
When this sacred and holy dictum is impressed on the heart, the domain of the heart turns by itself into the kingdom of God Almighty.
Then only man does not see anyone else as efficient in the realm of truth; he does not expect any rank, any distinction or riches from anybody else; he does not seek for honor and fame with the help of others; and his heart does not become hypocritical and profane, Imam Khomeini further explained.
Therefore, if you see that riya’ is stealing into your heart, you should realize that your heart has not really surrendered itself to reason, and faith has not illuminated your heart yet; for you consider others to be your God and see them as efficient agents in the world, and you do not trust Him, the only God; it means that you have joined the company of hypocrites, polytheists and idolaters.
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Imam Khomeini warned that human beings have a perilous and long journey ahead