Al-Kāfi - Volume 2 > Truthfulness and Trust
Hadith #7

7ـ ابْنُ أَبِي عُمَيْرٍ عَنْ مَنْصُورِ بْنِ حَازِمٍ عَنْ أَبِي عَبْدِ الله (عَلَيهِ السَّلام) قَالَ إِنَّمَا سُمِّيَ إِسْمَاعِيلُ صَادِقَ الْوَعْدِ لأنَّهُ وَعَدَ رَجُلاً فِي مَكَانٍ فَانْتَظَرَهُ فِي ذَلِكَ الْمَكَانِ سَنَةً فَسَمَّاهُ الله عَزَّ وَجَلَّ صَادِقَ الْوَعْدِ ثُمَّ قَالَ إِنَّ الرَّجُلَ أَتَاهُ بَعْدَ ذَلِكَ فَقَالَ لَهُ إِسْمَاعِيلُ مَا زِلْتُ مُنْتَظِراً لَكَ.

7. Ibn abu ‘Umayr has narrated from Mansur ibn Hazim from abu ‘Abd Allah (a.s.) who has said the following: “Isma’il is called the truthful in his promises; he promised a man to meet him at a certain place and Isma’il waited for him at that place for one year. Thus, Allah, the Most Majestic, the Most Holy, named him the truthful in his promise. The Imam then said, ‘The man then came at that place and Isma’il said to him, “I am still waiting for you.’””