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. 2 The heir is subject to guardians and trustees until the time set by his father. 3 So also, when we were underage, we were in slaveryw under the elemental spiritual forcesa of the world.x 4 But when the set time had fully come,y God sent his Son,z born of a woman,a born under the law,b 5 to redeemc those under the law, that we might receive adoptiond to sonship.b e 6 Because you are his sons, God sent the Spirit of his Sonf into our hearts,g the Spirit who calls out, “Abba,c Father.”h 7 So you are no longer a slave, but God’s child; and since you are his child, God has made you also an heir.i
Or under the basic principles
The Greek word for adoption to sonship is a legal term referring to the full legal standing of an adopted male heir in Roman culture.
Aramaic for Father