Sahih Muslim
Sahih Muslim 196 a
Regarding the saying of the Prophet (saws): "I will be the first of the people to intercede concerning Paradise, and I will be the Prophet with the Greatest Number of Followers."
Arabic hadith text
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، وَإِسْحَاقُ بْنُ إِبْرَاهِيمَ، قَالَ قُتَيْبَةُ حَدَّثَنَا جَرِيرٌ، عَنِ الْمُخْتَارِ بْنِ فُلْفُلٍ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم "أَنَا أَوَّلُ النَّاسِ يَشْفَعُ فِي الْجَنَّةِ وَأَنَا أَكْثَرُ الأَنْبِيَاءِ تَبَعًا "
Translation
Anas b. Malik reported
The Messenger of Allah (ﷺ) said: I would be the first among people to intercede in the Paradise and amongst the apostles I would have the largest following (on the Day of Resurrection).