The imagery of family is brought back up again. He had used the imagery in the past. The two nations were looked at as spouses that God had dearly loved but who had betrayed His trust and violated their covenant promises and were unfaithful to Him. Here He speaks to 
both nations as children. He had set them up with a special inheritance as any good father would. Jeremiah 3:19 says, “I said, how I would set you among my sons, and give you a pleasant land, a heritage most beautiful of all nations. And I thought you would call me, My Father, and would not turn from following me.”
He wants us to call him “My Father.” This is reminiscent of Jesus’ instruction on how to prayer. We are to begin our prayer by addressing Him as “Our Father.” We can come to Him as a little child comes to their daddies and call out “Abba Father,” which is a term of endearment. It’s also a term of complete dependence and trust. Little children especially can exhibit the most remarkable kind of trust. Jesus once told us that the Kingdom of Heaven was reserved for children or those who can find the faith of a child. When he faced crucifixion Jesus prayed that the cup of suffering that awaited Him might be passed over, but He ended His prayer with a childlike statement of trust. It is God’s will that matters and whatever that holds for me, I know I can trust Him because He is my Father!
John MacArthur quotes Martin Lloyd Jones who expounds on the Lord ’s Prayer. To Jones the most significant aspect of that prayer is the opening instruction on how to address God. He writes, “The sum of it all is that ultimately there is nothing in the whole realm of Scripture which so plainly shows us our entire dependence upon God as does this prayer, and especially these three petitions. The only thing that really matters for us is that we know God as our Father. If we only knew God like this our problems would be solved already and we would realize our utter dependence upon Him and go to Him daily as children to their Father.”[1] Going directly to Jones’ work he explains the importance of knowing God as “Father.” He writes, “We are born under the wrath of God. We do not know Him, and we are evil by nature. Our greatest need is to be reconciled to God, to have our sins forgiven, to know God as our Father, to be blessed by Him, and to start as a child of God. And Jesus came in order that men and women might know this. This is His message—not that we improve the world but that you and I be redeemed.”[2]
[1] John F. MacArthur Jr., Alone with God, MacArthur Study Series (Wheaton, IL: Victor Books, 1995), 90.
[2] David Martyn Lloyd-Jones, Authentic Christianity, 1st U.S. ed., vol. 1, Studies in the Book of Acts (Wheaton, IL: Crossway Books, 2000), 15.