The talk of Invisible Eye is not a mere moral discourse. We may look at it from a pragmatic angle.
In the early days of Islam, a destitute orphan girl was brought up in her uncle’s home along with her cousin (brother). When they became adult, on one occasion the boy, who loved her one-sidedly, proposed to her for his evil intensions. The girl, poor, helpless and subjected to her guardian’s family pursued her best to protect her modesty but in vain. When the boy tried to make the advancement, the girl said, “I am but to submit, but stop the Invisible Eye of Allah shall be watching.”
At this moment the boy got shaken and shivered, and uttered: “Go! Go out. Leave this place right now.” There was no fear of being seen, caught, beaten up or awarded with the Islamic penalty of getting stoned to death, as the incident was to take place in seclusion and loneliness; and the girl herself was not to divulge it to even her elders. It was only the belief of Accountability unto Allah on the Day of Judgement aroused instantly in him when reminded of this Invisible Eye watching him committing a great sin (Gunaah-e-Kabira) that did this miracle. In present secular and Godless societies, this cannot even be imagined.
A woman in the city of Madinah driven by the inherent animal instinct in humans committed adultery. She, afterwards, fell into a deep sense of guilt and sin. She knew well that no third person on earth has seen this illicit act of hers, and hence there is no chance of getting the penalty of stoning to death. Even then, she went to the Prophet, confessed her sin, and requested him to award the capital punishment being awarded to her. And she was awarded eventually with the verdict by the Prophet of ‘Rajm’ (being stoned to death).
Can anybody today in the secular society and Godless societal system even imagine this, and that too from a lady having an infant in her lap? No! Never ever! Then what was it that did this miracle? It was her strong faith in the Islamic creed that the Invisible Eye of Allah has seen her committing this great sin. And her firm faith in being accountable unto Allah on the Day of Judgment in the Life Hereafter. And her strong sense of conviction that she would not escape the wrath of Allah and shall be punished with Hell fire.
This was only up to herself to choose one of the two pains: One, being burnt in the Hell Fire for so long a time she couldn’t apprehend. The other, bearing the pain for short a while, until she dies of stoning. She chose the other pain. The Prophet appreciated her courage and commitment and her will power to surrender unto the God’s injunction.
This firm belief in Allah’s Invisible Eye watching man’s deeds every moment, everywhere is the sole reason of the difference palpably visible and observed between the societies developed by Islam and those by non-Islam, with respect to crimes and immoral acts like incest, post-/pre-marital sexual relations, female foeticide, infanticide, abortion, theft, robbery and crimes of sorts. The more Islam is let to form and shape the moral character of humans, the lesser are the socio-moral evils prevalent in a Muslim society.
So, Islam invites all humans to come to it, and to establish a society of highest moral character.