What does ‘Abba’ mean?

Luther:

That is Aramaic. It is the word what little children say when they talk with their father in childlike confidence and they say: ‘daddy, daddy’. The easiest word there is!

And by such words faith speaks through the Holy Spirit, to God, but then out of the heart and, as Paul says, with ‘groanings which cannot be uttered’ (Romans 8:26). Especially when we are afraid, when we struggle with something or when we are attacked by the devil. Then God’s children cry: ‘Oh dear Father, You are my dear Father, are You not? Because You have given Your only dear Son for me, therefore would You no longer be angry with me? You see how weak I am and how I need You, do You not? Oh dear Father, do You want to help and save me?’