|What kind of difference there is between the Shirk and the Kufr?|
Kufr is the disbelief of one or some religious basics which are known with certainty that the Prophet has brought them from Allah. Shirk, on the other hand, one’s belief of Allah’s having a partner (or partners) or an associate in His being the Lord, in His names, attributions, and actions, although he/she believes in Allah’s existence; or one’s setting up partners in worship with Allah.
Shirk and Kufr are very close terminologies. The difference between them is that kufr is more general and shirk is more private. Therefore every shirk is a kufr but every kufr is not a shirk. Shirk comes about as a result of by associating partners to Allah and His Self, name and attributes. Kufr comes into being by accepting some of the beliefs which is known that they are kufr.