If knowledge is useful without actions, Allah, the Exalted would never have dispraised the people of the book, and if actions were useful without devotion, He would never have dispraised the hypocrites.
(Imam Ibn Al-Qayyim – Al-Fawa’Id – A Collection Of Wise Sayings pg 54. )
Imaam Ibn Qayyim (rahimahullaah Ta’aala) said:
If bid’ah only consisted of lies, then it would NOT have been accepted and everybody would even hurry to condemn it and refute it. And if it only consisted of Haqq (truth), then it would not have been a Bid’ah, rather, in agreement with the Sunnah. But it (Bid’ah) consists of both truth and lies in which the truth is clothed with lies.
[as-Sawaa´iq al-Mursalah (3/925)]
Do Not Be Deceived By Ahlul-Bid’ah who may agree with the Salafees in certain matters
Shaqiq al-Balkhi said:
The sign(s) of (true) repentance are:
Crying over what has passed by (of one’s actions),
fear of falling into the sin (once again),
boycotting evil company, and
accompanying the righteous.
[Al-Siyar of al-Dhahabib (9/315)] – salaf.com
The Method Of Making Tawbah – Fatwa
Repentance (Tawba) – by Dr. Saleh as-Saleh (Rahimahullaah) – Transcribed
Yoonus ibn ‘Ubayd (d.139H) – rahimahullaah -said:
“With good manners you understand the knowledge. With the knowledge your actions are corrected. With actions wisdom is obtained. With wisdom you understand zuhd (abstinence) and are granted its benefits. With zuhd comes abandoning the world. With abandoning the world comes desire for the Hereafter. With desire for the Hereafter the pleasure of Allaah – the Mighty and Majestic – is obtained.”
A Return to Excellence
One of the Companions said:
You are doing deeds that are, in your eyes, more insignificant than a hair, whereas at the time of the Messenger of Allaah (‘alayhis-salaam) we would consider them to be destructive sins! 
ibn Rajab, the Journey to Allah
 al-Bukhaaree no. 6492 on the authority of Anas.
Imaam Ibn Seereen (rahimahullaah) said :
‘Indeed, This knowledge Is Deen,
So Look To The One You Take Your Deen From
‘Umar ibn Abdil-’Aziz said:
Become a scholar if you are able.
If you are not able, then be a student.
If you can not, then show love for them.
If you are unable to do that, then (at least) do not hate them.
[Ibn Abdil-Barr in Jaami’u Bayaanil-‘Ilmi wa Fadhlihi, #143]