Galatians 4:1-11 NIV
What I am saying is that as long as an heir is underage, he is no different from a slave, although he owns the whole estate. The heir is subject to guardians and trustees until the time set by his father. So also, when we were underage, we were in slavery under the elemental spiritual forces of the world. But when the set time had fully come, God sent his Son, born of a woman, born under the law, to redeem those under the law, that we might receive adoption to sonship. Because you are his sons, God sent the Spirit of his Son into our hearts, the Spirit who calls out, “ Abba, Father.” So you are no longer a slave, but God’s child; and since you are his child, God has made you also an heir.
Formerly, when you did not know God, you were slaves to those who by nature are not gods. But now that you know God—or rather are known by God—how is it that you are turning back to those weak and miserable forces? Do you wish to be enslaved by them all over again? You are observing special days and months and seasons and years! I fear for you, that somehow I have wasted my efforts on you.
NIV: New International Version