Hi, if you’re referring to the use of “Abba” in Romans 8:15, Paul is saying that the Christian does not speak from a position of slave (i.e. parentless and powerless), but rather, a son.

To say ‘Abba Father’ is to speak to God as a son who is the designated heir. This son matters, and his concerns pertain to the future of the family, so must be attended to.