Descriptions of Heaven in the New Testament are more fully developed than those in the Old Testament, but are still generally vague. As in the Old Testament, in the New Testament, God is described as the ruler of Heaven and Earth, but his power over the Earth is challenged by Satan. Sayings of Jesus recorded in the Gospels of Mark and Luke speak of the "Kingdom of God" (; ), while the Gospel of Matthew more commonly uses the term "Kingdom of Heaven" (; ). Both phrases have exactly the same meaning, but the author of the Gospel of Matthew changed the name "Kingdom of God" to "Kingdom of Heaven" in most instances because it was the more acceptable phrase in his own cultural and religious context in the late first century.