The word “Abba” is actually a “transliteration” of the Aramaic word “abba.” There are three places that abba” is found in the Bible; it occurs in the Greek New Testament in Mk. 14:36; Rom. 8:15; Gal. 4:6. This term, however, is never used in the LXX/Septuagint (the Greek version of the Old Testament). A simple definition for “abba” word is “father.”
It is true that in later times the Jewish people used the word “abba” in ways that we use the word “daddy,” but it is false to conclude that this term entitles people to think of God as “daddy,” “big daddy,” or “daddy in the sky.” In the New Testament “abba” is a respectful term that reminds people that God is a loving Father to those who seek to be His people.