Four of the Worst of the Major Sins

ʿAbdullāh b. Masʿūd – Allāh be pleased with him – said:

The worst of the worst (major) sins are: to associate partners with Allāh, to lose hope of the aid of Allāh, to despair of the mercy of Allāh, and to feel safe from the plans of Allāh.

Al-Ṭabarī, Al-Tafsīr (Qurān 4: 31). Graded ṣaḥīḥ by Ibn Kathīr in his tafsīr of the same verse.

The Viral Sin

It is reported that Al-Ḥasan Al-Baṣrī – Allāh have mercy on him – said:

We used to narrate: Whoever faults his brother for a sin he has repented to Allāh from, Allāh will try him with that very sin.

Aḥmad b. Ḥanbal, Al-Zuhd p342 (Al-ʿIlmīyah ed., 1983).

The Famous Fake

It is reported that Ibrāhīm b. Adham – Allāh have mercy on him – said:

A person has not been true to Allāh, the mighty and sublime, if he loves recognition (fame).

Aḥmad b. Ḥanbal, Al-Zuhd article 2240.

Benefiting from Happiness and Sadness

It is reported that ʿIkrimah – Allāh have mercy on him – said:

Everyone gets happy and gets sad, but you should turn your happiness into gratitude (to Allāh) and your sadness into patience (ṣabr).

Ibn Kathīr, Tafsir of Al-Ḥadīd: 23.

Do Not Beautify Yourself with Knowledge

It is reported that Ḥabīb b. ʿUbayd – Allāh have mercy on him – said:

Learn knowledge, understand it and benefit from it (live by it); and do not study it in order to decorate yourself with it, for if you live long you will likely see a time when knowledge will be used for beautification like a man beautifies himself with his garments.

Ibn Al-Mubārak, Al-Zuhd wa Al-Raqāʾiq no. 1056.