Because you are his sons, God sent the Spirit of his Son into our hearts, the Spirit who calls out, “Abba, Father.” Gal 4:6 NIV
The most amazing thing about the gospel is that we are invited into an intimate personal relationship with the triune God – Father, Son and Holy Spirit. Holy Spirit joins with our spirit in the welcome embrace of God the Father. We are adopted children. Holy Spirit embraces us confirming that we are sons and daughters indeed. And if sons and daughters then heirs of all his glorious heavenly riches.
14 For those who are led by the Spirit of God are the children of God. 15 The Spirit you received does not make you slaves, so that you live in fear again; rather, the Spirit you received brought about your adoption to sonship. And by him we cry, “Abba, Father.” 16 The Spirit himself testifies with our spirit that we are God’s children. 17 Now if we are children, then we are heirs—heirs of God and co-heirs with Christ, if indeed we share in his sufferings in order that we may also share in his glory. Rom 8:14-17 NIV
Jesus shares this intimate father/son relationship with us and shows us how to communicate with Abba Father.
9 “This, then, is how you should pray: “‘Our Father in heaven, hallowed be your name, 10 your kingdom come,
your will be done, on earth as it is in heaven. Mt 6:9-10 NIV
This example of prayer begins with the declaration of intimate family connection, but also goes on to convey a willingness to see the outworking of God’s will in the prayer’s life.
Jesus himself used the same terminology in his time of deepest need.
5 Going a little farther, he fell to the ground and prayed that if possible the hour might pass from him. 36 “Abba, Father,” he said, “everything is possible for you. Take this cup from me. Yet not what I will, but what you will.” Mk 14:35-36 NIV
Abba is a term of endearment, intimacy, and close relationship, on the one hand, and honour, respect, and obedience on the other hand. Jesus is in a trying time in the Garden of Gethsemane, so he withdraws to be alone with God in prayer. This is an intimate experience with the Father. However, the substance of Jesus’ prayer that begins with Abba also expresses a willingness to obey.