This Aramaic word is found 3 times in the New Testament (Mark 14:36; Romans 8:15; Galatians 4:6), and in each case is followed by its Greek near equivalent, which is translated “father.” It is a term expressing warm affection and confidence, with no perfect equivalent in English. The word “Daddy” perhaps comes the closest.
And He [Christ] was saying,
“Abba! Father! All things are possible for You;
remove this cup from Me;
yet not what I will, but what You will.” —Mark 14:36 NASB
For you have not received a spirit of slavery leading to fear again, but you have received a spirit of adoption as sons by which we cry out, “Abba! Father!” —Romans 8:15 NASB
Because you are sons, God has sent forth the Spirit of His Son into our hearts, crying, “Abba! Father!” —Galatians 4:6 NASB
The word passed into European languages as the ecclesiastical term “abbot.”