It is reliably transmitted from ʿUmar ibn al-Khaṭṭāb—may Allah be pleased with him—and the Muslims are unanimously agreed that whoever denies the obligation of the five pillars of Islam—the two testimonies of faith, the five daily prayers, the alms-tax, fasting the month of Ramadan, and the pilgrimage to the House—is a disbeliever.

Moreover, the Exalted One says at the beginning of the surah:

“Allah bears witness that there is no deity except Him, and so do the angels and those endowed with knowledge, upholding justice. There is no deity except Him, the Almighty, the All-Wise.” ⦗Āl ʿImrān 3:18⦘

(18)

“Truly, the religion in Allah’s sight is Islam. Those who were given the Scripture differed only after knowledge had come to them, out of mutual envy. Whoever rejects Allah’s signs—surely Allah is swift in reckoning.” ⦗Āl ʿImrān 3:19⦘

(19)

“So if they argue with you, say, ‘I have submitted my face to Allah, and so have those who follow me.’ And say to those who were given the Scripture and to the unlettered people, ‘Have you submitted?’ If they submit, they are rightly guided; but if they turn away, your duty is only to convey the message. Allah is All-Seeing of His servants.” ⦗Āl ʿImrān 3:20⦘