Allah’s Messenger (ﷺ) said:
"By Him in Whose Hands my life is, none of you will have faith till he loves me more than his father and his children."

قال رسول الله ﷺ : فوالذي نفسي بيده، لا يؤمن أحدكم حتى أكون أحب إليه من والده وولده.

‏صحيح البخاري (14)

Muhammad Ibn Sirin [d.110H] said:

‎“This knowledge is a religion, so consider from whom you receive your religion.”

‎[سير أعلام النبلاء ٦/٦١١]

O Allah, the Revealer of the Holy Book, and the Mover of the clouds and the Defeater of the clans, defeat them, and grant us victory over them.

اللَّهُمَّ مُنْزِلَ الْكِتَابِ وَمُجْرِيَ السَّحَابِ وَهَازِمَ الأَحْزَابِ اهْزِمْهُمْ وَانْصُرْنَا عَلَيْهِمْ

Sahih al-Bukhari 3024

Imām Ahmad Ibn Hanbal رحمه الله was asked:

“Can I pray behind an alcoholic?”

He said: “No”

The man said:

“So what about praying behind the one who says the Qur’ān is created?”

He said:

“Glory to Allāh! I prevented you from the Muslim (sinner), then you ask me about a Kāfir?”

Hudhayfah رضي الله عنه was asked:

“What is the worst fitnah?” He replied, “That good and evil is presented to you and you do not know which of them to follow.”

[Ibn Abī Shaybah, Al Musannaf, Kitab Al-Fitan, article 38565.]

Ibn Taymiyyah said:

“And the philosophers are in a worse state than the Jews and the Christians.”

وَالْمُتَفَلْسِفَةُ أَسْوَأُ حَالًا مِنَ الْيَهُودِ وَالنَّصَارَى

[Majmu' al-Fatawa 7/586]

Abdullah ibn Mas'ud said:

"Verily, hearts are containers, so fill them with the Quran and do not fill them with anything else."

[Imam Ahmad, Al-Zuhd 891]

Yahya related to me from Mālik from Da'ud ibn al-Husayn that he heard al-Araj say:

"I never saw the people in Ramadan, but that they were cursing the disbelievers."

Muwatta Imām Mālik
كتاب الصلاة فى رمضان

‎On authority of 'Ibn Mas'ūd:

‎"We were prohibited from responding to whoever invites the wealthy and neglects the poor [to a wedding feast]..."

‎Related by Ibn Battal in Sharh Sahih al-Bukhari, 7/289

‎عن ابن مسعود أنه قال: نهينا أن نجيب من يدعو ‌الأغنياء ويترك ‌الفقراء