التفسير التبليغي
(Rather, they wondered that a warner had come to them from among themselves, and the disbelievers said, "This is a wondrous thing!") (2)
(بَلْ عَجِبُوا أَنْ جَاءَهُمْ مُنْذِرٌ مِنْهُمْ) They wondered at a matter from which they ought not to have wondered, and that is the essence of religion.
Most people do not appreciate Allah's blessings as they should.
His saying: (مِنْهُمْ) meaning they know his lineage, truthfulness, and trustworthiness.
(أَنْ جَاءَهُمْ مُنْذِرٌ) meaning he warned them with a true warning from the punishment of Allah.
His saying: (هَذَا شَيْءٌ عَجِيبٌ) is a reference to the coming [of the warner].
Qatadah said: Their wonder was that they were called to one God.
(فَقَالَ الْكَافِرُونَ هَذَا شَيْءٌ عَجِيبٌ) meaning, yet this is not wondrous; for Allah chooses messengers from among the angels and from among mankind.
(فَقَالَ الْكَافِرُونَ هَذَا شَيْءٌ عَجِيبٌ) meaning, this resurrection that you, O Muhammad, tell us about, is something to be wondered at, and our understandings are left bewildered before it.
Source: التفسير التبليغي