Al-Kāfi - Volume 1 > Setting-up a Time Limit for the Reappearance of the Twelfth Imam (a.s.) an Antipathetic Issue
Hadith #7

7ـ الْحُسَيْنُ بْنُ مُحَمَّدٍ عَنْ جَعْفَرِ بْنِ مُحَمَّدٍ عَنِ الْقَاسِمِ بْنِ إِسْمَاعِيلَ الانْبَارِيِّ عَنِ الْحَسَنِ بْنِ عَلِيٍّ عَنْ إِبْرَاهِيمَ بْنِ مِهْزَمٍ عَنْ أَبِيهِ عَنْ أَبِي عَبْدِ الله (عَلَيْهِ السَّلام) قَالَ ذَكَرْنَا عِنْدَهُ مُلُوكَ آلِ فُلانٍ فَقَالَ إِنَّمَا هَلَكَ النَّاسُ مِنِ اسْتِعْجَالِهِمْ لِهَذَا الامْرِ إِنَّ الله لا يَعْجَلُ لِعَجَلَةِ الْعِبَادِ إِنَّ لِهَذَا الامْرِ غَايَةً يَنْتَهِي إِلَيْهَا فَلَوْ قَدْ بَلَغُوهَا لَمْ يَسْتَقْدِمُوا سَاعَةً وَلَمْ يَسْتَأْخِرُوا.

7. Al-Husayn ibn Muhammad has narrated from Ja’far ibn Muhammad from al-Qasim ibn ’Isma‘il al-Anbari from al-Hassan ibn Ali from Ibrahim ibn Mihzam from his father who has said the following. “We mention before abu ‘Abdallah (a.s.) the Kings from the descendants of so and so. The Imam (a.s.) said, “People have perished due to their haste for this matter ((the rise of al-Mahdi with Divine Authority). Allah does not expedite it because of the haste of people. For this matter (the rise of al-Mahdi with Divine Authority) there is a goal towards which it proceeds, Once they will reach that goal they then will not be able to move it forwards or backwards even by one hour.”