What is meant by Sheikh Al-Islam Ibn Taymiyyah's statement that among the prerequisites of faith is not to show loyalty to the enemies of Allah, and that showing them loyalty is evidence of the absence of the obligatory faith in the heart?

Belief in Allah necessitates disavowal of His enemies. Befriending disbelievers (mowalat al-kuffar) is an act of disbelief that contradicts the obligatory faith, as Allah Almighty says: (You will not find a people who believe in Allah and the Last Day loving those who oppose Allah and His Messenger). And whoever takes disbelievers as allies is not a believer, and whoever befriends them is one of them. Allah Almighty says: (And whoever does that has no relation with Allah whatsoever, unless you guard yourselves against them with a [due] caution). And befriending disbelievers has different degrees; some of it is major disbelief, and some is less than disbelief.