Sunan Ibn Majah, Book 36, Hadith 69 (In-Book) ⓘ
It was narrated from Abu Hurairah that the Messenger of Allah said: “You will most certainly follow the ways of those who came before you, arm’s length by arm’s length, forearm’s length by forearm’s length, hand span by hand span, until even if they entered a hole of a mastigure (lizard) you will enter it too.” They said: “O Messenger of Allah, (do you mean) the Jews and the Christians?” He said: “Who else?”
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا يَزِيدُ بْنُ هَارُونَ، عَنْ مُحَمَّدِ بْنِ عَمْرٍو، عَنْ أَبِي سَلَمَةَ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " لَتَتَّبِعُنَّ سُنَّةَ مَنْ كَانَ قَبْلَكُمْ بَاعًا بِبَاعٍ وَذِرَاعًا بِذِرَاعٍ وَشِبْرًا بِشِبْرٍ حَتَّى لَوْ دَخَلُوا فِي جُحْرِ ضَبٍّ لَدَخَلْتُمْ فِيهِ " . قَالُوا يَا رَسُولَ اللَّهِ الْيَهُودُ وَالنَّصَارَى قَالَ " فَمَنْ إِذًا " .
also referenced under: Hadith 3994 (Reference) & Volume 5, Book 36, Hadith 3994 (DarusSalam)