Allah said,

﴿وَمَن كَفَرَ فَإِنَّ الله غَنِىٌّ عَنِ الْعَـلَمِينَ﴾

(...and whoever disbelieves, then Allah stands not in need of any of the `Alamin) ﴿3:97﴾.

Ibn `Abbas, Mujahid and several others commented on this Ayah, "Whoever denies the necessity of Hajj becomes disbeliever, and Allah is far Richer than to need him.'' Al-Hafiz Abu Bakr Al-Isma`ili recorded that `Umar bin Al-Khattab said, "Whoever can afford Hajj but did not perform it, there is no difference in his case if he dies while Jew or Christian.'' This has an authentic chain of narration leading to `Umar.

﴿قُلْ يأَهْلَ الْكِتَـبِ لِمَ تَكْفُرُونَ بِـَيَـتِ اللَّهِ وَاللَّهُ شَهِيدٌ عَلَى مَا تَعْمَلُونَ - قُلْ يأَهْلَ الْكِتَـبِ لِمَ تَصُدُّونَ عَن سَبِيلِ اللَّهِ مَنْ ءَامَنَ تَبْغُونَهَا عِوَجاً وَأَنْتُمْ شُهَدَآءُ وَمَا اللَّهُ بِغَـفِلٍ عَمَّا تَعْمَلُونَ ﴾

(98. Say: "O People of the Scripture (Jews and Christians)! Why do you reject the Ayat of Allah, while Allah is Witness to what you do'') (99. Say: "O People of the Scripture (Jews and Christians)! Why do you stop those who have believed, from the path of Allah, seeking to make it seem crooked, while you (yourselves) are witnesses And Allah is not unaware of what you do.'')