How can we reconcile the Hadith, "No servant says 'La ilaha illa Allah' (There is no god but Allah) and then dies upon that, except that he enters Paradise," with the eternal damnation of polytheists (mushrikin) and hypocrites (munafiqin) in Hellfire, even though they say "La ilaha illa Allah"?

The hadith indicates that whoever says "Lā ilāha illallāh" is a believer, even if they commit sins or major transgressions. The creed of Ahl al-Sunnah wal-Jamāʿah is that a believer who commits major sins will ultimately enter Paradise, and if they are punished before that, it is subject to the will of Allah, as stated in His glorious words: "Indeed, Allah does not forgive association with Him, but He forgives what is less than that for whom He wills." As for the hypocrites and the people of disbelieving innovations, they did not say "Lā ilāha illallāh" with sincere hearts. Their innovations contradict the saying of the Messenger, peace and blessings be upon him, "Whoever says Lā ilāha illallāh will enter Paradise." Therefore, sincerity in the two testimonies of faith is essential. The hypocrites utter the two testimonies with their tongues, but their hearts are devoid of faith, and their ultimate destination is the lowest depths of the Hellfire.