One of the most obvious differences between the Old Testament and New Testament is how God is referred to. In the Old Testament, God is called the Father of the nation of Israel or of certain individuals 15 times (although father imagery is sometimes used). But in the Gospels, God is referred to as Father some 165 times! And the apostle Paul refers to God as Father some 40 different times in his epistles.

It is thought by scholars that Jesus, and most of His contemporaries, spoke Aramaic, a dialect of Hebrew. The word they would have used for “father” was the Aramaic word abba, a personal and intimate word. When the New Testament was recorded in Greek, most occurrences of abba were translated with the Greek word pater—but abba is preserved in three instances: Mark 14:36, Romans 8:15-16, and Galatians 4:6. Each of these verses reflects a level of personal intimacy which abba conveys. It has been suggested that abba is the equivalent of the modern word “daddy”—the way a child addresses his father.

When you address God as Father in prayer, reflect on the fact that you are His child, adopted into His forever family (Galatians 4:4-7).

A Christian is one who has God as his Father.
J. I. Packer