Question 1: Obligation to Declare Takfeer?
There are some principles that some youth act on, O Shaykh. Amongst them are that whoever does not declare a Kafir to be a Kafir is a Kafir himself. Whoever does not declare an innovator to be an innovator is an innovator himself. Whoever is not with us is against us. What do you think, O Shaykh?
And where did these principles come from, and who is it that instituted them?
This reminds me of a joke in my country of origin, Albania, that my father, may Allaah have mercy upon him, used to tell: