Ibn Majah

Benefits and Issues:

➊
Worshipping anyone besides Allah is shirk (polytheism).
Whoever does not perform prayer (salah) has abandoned the worship of Allah
and has begun the worship of Satan.
Because obeying Satan in opposition to Allah’s command is, in reality, worship of Satan.
Then what doubt remains in the polytheism of the worshippers of Satan?
The statement of Allah, the Exalted, is:
﴿وَأَقِيمُوا الصَّلَاةَ وَلَا تَكُونُوا مِنَ الْمُشْرِكِينَ﴾ (al-Rum: 31)
“And establish prayer, and do not be among the polytheists.”
That is, while calling the believers to the religion and admonishing them, in the end, this advice was given: do not become among the polytheists.
As if the polytheists do not perform prayer, but a believer cannot even imagine abandoning it.

➋
Except for abandoning prayer, no one who commits a major sin (kabirah) can be declared a disbeliever (kafir) or polytheist (mushrik), except for those actions which are, in reality, acts of disbelief (kufr) and polytheism (shirk).
Wherever the word kufr has been used for such actions, it means that these actions do not befit Muslims.
If the disbelievers do them, so be it. For example, the statement of the Prophet sallallahu alayhi wa sallam: (Sibabu al-muslim fusuqun wa qitaluhu kufrun)
(Sahih Muslim, al-Iman, Chapter: Explanation of the Prophet’s statement “Abusing a Muslim is wickedness and fighting him is disbelief,” Hadith: 64)
“Abusing a Muslim is wickedness, and fighting him is disbelief.”
Along with this, those who fight each other have also been called Muslims.
Allah, the Exalted, said:
﴿وَإِن طَائِفَتَانِ مِنَ الْمُؤْمِنِينَ اقْتَتَلُوا فَأَصْلِحُوا بَيْنَهُمَا﴾ (al-Hujurat: 9)
“If two groups among the believers fight each other, then make peace between them.”

➌
The mentioned narration is weak in its chain (isnad).
However, its meaning is correct.
Most likely for this reason, other scholars have declared it authentic. See: (Sahih al-Targhib, by al-Albani, nos. 567, 565; Sunan Ibn Majah, Dr. Bashar Awwad: 1080)