From Galatians 4 (with a couple thoughts):
"But when the proper time came God sent his son, born of a human mother and born under the jurisdiction of the Law, that he might redeem those who were under the authority of the Law and lead us into becoming, by adoption, true sons of God." What a wonderful truth is the Incarnation! Up to that day, God had had no personal experience of either the frailty of our flesh or the Law’s steep demands, but, at the “proper time,” He chose to take on both. And in day-by-day walking perfectly under the Law’s “jurisdiction,” He has shown that His Way defeats sin, fulfills the Law and makes us son and daughters who are fully approved. And how do we know that we’re His children? "It is because you really are his sons that God has sent the Spirit of his Son into your hearts to cry 'Father, dear Father.'" The presence of the Holy Spirit proves our son- and daughtership! The Holy Spirit is the stamp of our acceptability in the royal household! You often hear “conservative evangelical” types who say they’re “becoming more comfortable with all this Holy Spirit stuff…” What?! That’s like becoming more comfortable with breathing oxygen! The Holy Spirit is literally LIFE to us!
Let's live our lives FULLY, as sons and daughters, by FULLY engaging with His Holy Spirit. The truest thing about us is the truest thing in us - the indwelling Spirit of Christ!