Almighty Allah says:

"And he went into his garden while in a state, unjust to himself. He said: I think not that this will ever perish and I think not that the Hour will ever come, and if indeed I am brought back to my Lord (on the Day of Resurrection) I surely shall find better than these two (gardens) when I return to Him. His companion said to him during the talk with him: Do you disbelieve Him Who created you out of dust (i.e., your father Adam), then out of a drop of semen, then fashioned you into a man? But as for my part (I believe) that He is Allah, my Lord, and none shall I associate as partners with my Lord." (Holy Qur'an 18:35-38)

(d) "Al-Kufr-al-Irad" This implies turning away from the Truth knowingly or deviating from the obvious Signs which Allah has revealed.

Almighty Allah says:

"We created not the heavens and the earth and all that is between them except with Truth and for an appointed term. But those who disbelieve turn away from that whereof they are warned." Holy Qur'an (46:3)

(e) "AI-Kufr-an-Nifaq". This implies hypocritical disbelief.

Almighty Allah says:

"They have made their oaths a screen (for their hypocrisy) thus they hinder (men) from the Path of Allah. Verily, evil is what they used to do. That is because they believed, then disbelieved, so a seal was set on their hearts, therefore they understand not." (Holy Qur'an 63:2-3)

(2) The Minor Disbelief (Al-Kufr-Al-Asghar): This aspect of disbelief does not exclude one from the fold of Islam. It is also termed "Al-Kufr-an-Ni'mah." This implies disbelief manifesting itself in ungratefulness for Allah's blessings or favours.

Almighty Allah says:

"And Allah sets forth a parable, a township (Mecca) that dwelt secure and well-content, its provisions coming to it in abundance from every place; but it (its people) denied the favour of Allah with ungratefulness so Allah made it taste the pangs of hunger and terror because of the evil (i.e. denying Prophet Muhammad) which (its people) used to do." Holy Qur'an (16:112).