On whom is the term "kafir" (disbeliever) applied?

Question:
May Allah reward you with good and do you good. A message was sent from Yemen by a listener who says, "Abu Jim." Our brother asks a number of questions, one of which is: On whom is the term "kafir" applied? The term "kafir" is applied to one who disbelieves in Allah (Glorified and Exalted is He) by word, deed, or belief.

Answer:
One who commits an act of disbelief that takes him out of the religion is called a kafir. So, one who calls upon other than Allah, or seeks aid from other than Allah, or slaughters for other than Allah—meaning, seeks aid from other than Allah for something that only Allah is capable of doing—this is considered kufr (disbelief) and shirk (associating partners with Allah) in Allah (Mighty and Majestic). This type of kafir is of two kinds: the original kafir, who has lived in kufr from the beginning, and the murtadd (apostate), who entered Islam and then committed one of the nullifiers of Islam; he is considered an apostate. Yes. May Allah reward you with good.