"And because you are sons, God has sent the Spirit of His Son into our hearts, crying out, 'Abba! Father!'" (Galatians 4:6, BSB)
In a crowded mall, a toddler spots his father and shouts "Papa!" He doesn't think about grammar. He doesn't wonder if he's allowed. The word just comes out, and Papa turns round at once. Paul says something like that is going on inside you. "God has sent the Spirit of His Son into our hearts, crying out, 'Abba! Father!'" Notice who's crying out. The Spirit does, from inside you. It's not first your effort to feel close. It's the Spirit of the Son joining His voice with yours. You already belong, and the cry already rises. Look at the verses before it. Paul says that, while a child is young, he's no better than a slave, kept under guardians until the time set by the father (Galatians 4:1-3). Israel under the Law was like that: watched over, managed, kept at a distance. That was the old order, the elementary teaching.