The answer
The picture of the devil that we find in many of the books of the Old Testament is that he is an oppressor who opposes the righteous. The New Testament — especially the Book of Revelation — speaks of the devil and his character, thoughts, his enmity with humanity, and his desire to destroy us.
God created the devil and his angels with the rest of the angels, but through pride, the devil fell from his rank (Isa. 14:12–14). He desired to sit on the throne of God. His angels followed him and fell with him from heaven.
The devil took the form of a serpent in order to deceive Eve (Gen. 3:1–6). The Book of Wisdom tells us, “but through the devil’s envy death entered the world” (Wisd. of Sol. 2:24). Our Savior called him “the great dragon, the serpent of the old, Satan and the devil who deceives the whole world” (Rev. 12:9, 20:2). He afflicted Adam and Eve with [spiritual] blindness, so they chose sin instead of the light of divine truth. They lost their awareness of God’s will and His plan of salvation. Our Lord emphatically told us that Satan was a murderer from the beginning and does not abide in the truth because he is a liar and the father of lies (John 8:44).
Fr. Tadros Yacoub Malaty