The Peak of Eloquence · Hadith 909 (#Passage #4)

[صعوبة الإيمان :] إِنَّ أَمْرَنا صَعْبٌ مُسْتَصْعَبٌ، لاَ يَحْتَمِلُهُ إِلاَّ عَبْدٌ مُؤْمِنٌ امْتَحَنَ اللهُ قَلْبَهُ لِلاِيمَانِ، وَلاَ يَعِي حَدِيثَنَا إِلاَّ صُدُورٌ أَمِينَةٌ، وَأَحْلاَمٌ رَزِينَةٌ.

[Arduousness of belief :] Certainly, our case is difficult and complicated. No one can bear it except a believer whose heart Allāh has tried with belief. Our traditions will not be preserved except by trustworthy hearts and (men of) solid understanding.

Gradings are classical jarḥ-wa-taʿdīl, name-matched to a rijāl index (not individually re-verified).