A: The Iman (belief) of this person is incomplete and the same applies to those who commit some sins, their Iman diminishes, according to the opinion of Ahl­ul­Sunnah wal­Jama'ah (adherents to the Sunnah and the Muslim mainstream). They say that Iman is translated into words, deeds, and 'Aqidah (creed) which increases by acts of obedience and decreases by acts of disobedience. For example: abandoning Sawm (Fast) during the whole or part of Ramadan with no excuse is a grievous sin that decreases and weakens Iman. Some scholars deem the person who does this a Kafir (disbeliever).

The correct opinion is that such a Muslim is not deemed a Kafir by doing this, as long as they admit that Sawm is obligatory, but do not observe Sawm on some days out of negligence and laziness.

The same applies to a Muslim who does not give out Zakah (obligatory charity) on its due time out of slackness or do not give it out at all, this constitutes a grievous sin and is due to weak Iman.

The same applies to a Muslim who cuts off the ties of kinship or is undutiful to their parents. This is considered a lack and weakness of Iman and so are the rest of sins.

Regarding the abandonment of Salah (Prayer), it contradicts Iman and constitutes Riddah (apostasy from Islam), even if the person who abandons Salah do not deny its obligation. This is based on the more correct of the two opinions of the scholars, because the Prophet (peace be upon him) said: The head of the matter is Islam, its pillar is the Salah and the its highest peak is Jihad (fighting/striving in the Cause of Allah). Moreover, the Prophet (peace be upon him) said: The covenant between us and them is Salah; anyone who abandons it has committed Kufr (disbelief). There are other Hadiths indicating the same meaning.