In most of the scriptures, the Supreme Father figure is originally presented as upholder of the Law that every action has equal and opposite reaction. Later writers would come presenting a son of God who would exhibit a soft approach towards consequences of action. One of the best examples is John 7:53 to 8:11 which is now accepted as one of the most famous forgeries in the Bible.
Matthew 17:21 (“This kind does not go out except by prayer and fasting”) is a duplicate of Mark 9:29 ( "This kind can come out only by prayer.). It was apparently added by a copyist in order to make Matthew agree with Mark. Interestingly, the whole account in Mark 9:14-29 itself is a forgery [Because Jesus is presented as a simpleton as he calls the demon as “deaf and mute” yet commands him “to come out of him and never enter him again.” (Mark 9:25)]; this makes Matthew 17:21 a type of double-layered forgery!
Translators too are no exception:
1) Isaiah 66:3:
“Whoever slaughters an ox is just like one who kills a human being” (International Standard Version)
“When such people sacrifice a bull, it is no more acceptable than a human sacrifice” (New Living Translation)
2) Mathew 16:18 is the best example of how churches try to modify translation to support their favored doctrines.
On what basis do believers put trust in scriptures?