Narrated Safinah:

The Prophet ﷺ said: The Caliphate of Prophecy will last thirty years; then Allah will give the Kingdom of His Kingdom to anyone He wills.

Sa'id told that Safinah said to him: Calculate Abu Bakr's caliphate as two years, 'Umar's as ten, 'Uthman's as twelve and 'Ali so and so. Sa'id said: I said to Safinah: They conceive that 'Ali was not a caliph. He replied: The buttocks of Marwan told a lie.

حَدَّثَنَا سَوَّارُ بْنُ عَبْدِ اللَّهِ، حَدَّثَنَا عَبْدُ الْوَارِثِ بْنُ سَعِيدٍ، عَنْ سَعِيدِ بْنِ جُمْهَانَ، عَنْ سَفِينَةَ، قَالَ قَالَ رَسُولُ اللَّهِ ﷺ
" خِلاَفَةُ النُّبُوَّةِ ثَلاَثُونَ سَنَةً ثُمَّ يُؤْتِي اللَّهُ الْمُلْكَ - أَوْ مُلْكَهُ - مَنْ يَشَاءُ " . قَالَ سَعِيدٌ قَالَ لِي سَفِينَةُ أَمْسِكْ عَلَيْكَ أَبَا بَكْرٍ سَنَتَيْنِ وَعُمَرَ عَشْرًا وَعُثْمَانَ اثْنَتَىْ عَشْرَةَ وَعَلِيٌّ كَذَا . قَالَ سَعِيدٌ قُلْتُ لِسَفِينَةَ إِنَّ هَؤُلاَءِ يَزْعُمُونَ أَنَّ عَلِيًّا عَلَيْهِ السَّلاَمُ لَمْ يَكُنْ بِخَلِيفَةٍ . قَالَ كَذَبَتْ أَسْتَاهُ بَنِي الزَّرْقَاءِ يَعْنِي بَنِي مَرْوَانَ .