The Ruling on One Who abandons Prayer and on One Who prays in His House or delays the Prayer from its Appointed Time

Question :

What is the ruling on abandoning prayer? And what is the ruling on one who neglects prayer in congregation with the Muslims and prays in his house? And what is the ruling on one who delays the prayer from its appointed time?

Answer:

These are three questions; as for the first question, abandoning prayer is disbelief which takes one outside the pale of Islam. So whoever does not pray is a disbeliever, outside the fold of Islam, and if he is married, his marriage to her is annulled. Any animal which he slaughters is not permissible to be eaten and fasting is not accepted from him, nor is charity, and it is not permissible for him to go to Makkah and enter the Haram. If he dies, it is not permissible for him to be washed, shrouded and prayed over nor may he be buried with the Muslims. Instead, he should be taken out to the desert, a hole dug for him and he should be buried therein. If anyone had a relative who died and he knows that he did not pray, he must not deceive the people by bringing the deceased to them in order for them to pray over him, because prayer over a disbeliever is forbidden according to the Words of Allah, the Most High:

And never (O Muhammad) pray (funeral prayer) for any of them who dies, nor stand at his grave. Certainly they disbelieved in Allah and His Messenger.

And because Allah says:
It is not (proper) for the Prophet and those who believe to ask Allah's forgiveness for the Mushrikun (polytheists, idolaters, pagans and disbelievers in the Oneness of Allah) even though they be of kin, after it has become clear to them that they are dwellers of the Fire (because they died in a state of disbelief).

As for one who does not pray in congregation, praying (instead) in his house, he is a Fasiq, not a disbeliever; but if he continues to do so, he belongs to the party of sinners and the characteristic of being just is negated from him.

Regarding one who delays the prayer until after its appointed time, he is a worse sinner than the one who does not pray in congregation, because he delays it, in addition to his not praying in congregation, although he is a lesser sinner than one who abandons it completely. At all events, the matter of prayer is a most important one, and it is incumbent upon the believer to preserve it because it is a pillar of Islam, as the Prophet said. And whoever has no pillars in his house, his house will not remain standing permanently, therefore, the Muslims must advise one another and order each other to perform it and guard it strictly.

Source:
Ibn 'Uthaimin
Fatawa Islamiyah, Vol. 2 Pages 391-392