John 8:44

Finally Jesus identified the father of these Jews to whom He had been alluding (John 8:38; John 8:41). Their attitudes and actions pointed to the devil as their father for two reasons. They wanted to kill Jesus, and Satan was a murderer from the beginning of his career as a fallen angel. He indirectly murdered Adam and then Abel. Second, they had abandoned the truth for lies, and the devil had consistently done the same thing throughout history (cf. Genesis 2:17; Genesis 3:17). [Note: See Gregory H. Harris, "Satan’s Work as a Deceiver," Bibliotheca Sacra 156:622 (April-June 1999):190-202.]

In one sense every human being is a child of the devil since we all do the things that He does out of a sinful human nature. We usually think of this sinful behavior as identifying fallen Adam as our father, but Satan was behind the Fall. However the believer is also a child of God by faith in Jesus Christ. Consequently we are always either manifesting the traits of one of our spiritual fathers or the other. This is the result of walking either by the flesh or by the Spirit.