Sunan Abi Dawud 21042
In-book no 538حَدَّثَنَا مُحَمَّدُ بْنُ كَثِيرٍ، حَدَّثَنَا سُفْيَانُ، حَدَّثَنَا أَبُو يَحْيَى الْقَتَّاتُ، عَنْ مُجَاهِدٍ، قَالَ كُنْتُ مَعَ ابْنِ عُمَرَ فَثَوَّبَ رَجُلٌ فِي الظُّهْرِ أَوِ الْعَصْرِ قَالَ اخْرُجْ بِنَا فَإِنَّ هَذِهِ بِدْعَةٌ .
Narrated Abdullah ibn Umar: Mujahid reported: I was in the company of Ibn Umar. A person invited the people for the noon or afternoon prayer (after the adhan had been called). He said: Go out with us (from this mosque) because this is an innovation (in religion).