Shaykh Abdul Kareem al Khudayr says:
"(Islamic) knowledge is not except by way of the Quran and Sunnah"
And he said:
"If someone knows the evidence but does not act upon them or acts in opposition to them then he is in reality ignorant (Jahl) even though he knows the evidences.
For example if he knows Ribba is Haram yet he eats it anyway them he is a Jahl even if people call him an Aalim"
"(Islamic) knowledge is not except by way of the Quran and Sunnah"
And he said:
"If someone knows the evidence but does not act upon them or acts in opposition to them then he is in reality ignorant (Jahl) even though he knows the evidences.
For example if he knows Ribba is Haram yet he eats it anyway them he is a Jahl even if people call him an Aalim"