Quotes from James D.G. Dunn

the conclusion that Jesus said `Abba' to God for precisely the same reason that (most of) his contemporaries refrained from its use in prayer - viz., because it expressed his attitude to God as Father, his experience of God as one of unusual intimacy.60

The evangelists therefore intend their readers to understand that Jesus' consciousness of divine sonship was a fundamental factor in his decision to move out into the public eye.