Why is faith in Christ important for our sonship?

Faith is essential in the context of our sonship because it operates as the means by which the truth of our identity is revealed. As stated in Galatians 4:6, God sends His Spirit into our hearts, prompting us to cry out to Him as 'Abba, Father.' This cry is both a sign of our relationship with God and an affirmation of our identity as His children. While we are made sons by God's purpose and Christ's sacrifice, our faith is the visible manifestation of that relationship, as those who are truly His will inevitably respond in faith. Thus, faith does not create our sonship but confirms and expresses it.