The main purpose of the Qur’an is to awaken in man a constant and unfailing awareness of God’s Presence; for in the words of the Qur’an, God “is closer to man than his jugular vein”. A God-conscious person knows that even if he doesn’t see God, God is always watching him:

Allah is the Light of the Universe; and the similitude of His Light is as a Niche in which is a Lamp enclosed in a Glass like a brilliant star; (the Lamp is) lit from a blessed Tree, an Olive, neither of The East nor of the West, whose oil is very luminous, though fire has not touched it. Light upon Light! God does guide whom He wills to His Light: And God sets forth parables for men; and He knows all things. (24: 35)

Allah—there is no god but He, the Living, the Self-Subsisting Supporter of all; no slumber can overtake him, nor sleep; His are all things in the heavens and on earth. Who can intercede with Him except with His permission? He knows what is before them or behind them. Nor can they compass anything of His knowledge except as He wills. His Throne extends over the heavens and the earth. He feels no fatigue in guarding and preserving them. For He is the Highest, the Supreme (in glory). (2:255)
Allah is the Protector of those who have faith: From the depths of Darkness, He leads them forth into Light. As for those who reject faith, their patrons are the Evil Ones, and they lead them from Light into the depths of Darkness. They are the companions of the Fire; and they will dwell therein for ever. (2: 257)
He is Allah in the Heavens and on earth. He knows what you hide and what you reveal, and He knows what you earn (by your deeds). (6:3)
To Allah belong the East and the West; and wherever you turn, there is the Face of Allah. For Allah is All- Embracing, All- Knowing. (2:115)
Your Guardian Lord is Allah, Who created the heavens and the earth in six stages, then He settled Himself on the Throne: He draws the night as a veil over the day, each in rapid succession: And the sun, the moon, and the stars, all are subservient to Him by His command; certainly, His are the Creation and the Command; Glorious is Allah, the Cherisher and Sustainer of the Worlds. (7: 54)
How can you reject faith in Allah?-- Seeing that you were without life and Allah gave you life; then will He cause you to die, and again He will bring you to life; and then again to Him will be your return. It is He Who has created for you all things that are on earth; then He turned to the heaven and made it into seven firmaments; and of all things He has perfect knowledge. (2: 28, 29)
(Allah) the Most Merciful! It is He Who taught the Qur’an. He created man: He taught him the power of speech. The sun and the moon follow (precise) courses pre-ordained. And the plants and the trees –both bow in His worship. And the Firmament has He raised high, and He has set up the Balance of Justice, in order
that you may not transgress due proportion. (55: 1-8)