In Galatians 4:7, Paul says, Therefore you are no longer a slave but a son, and if a son, then an heir of God through Christ. (NKJV)

Before God’s calling, we were all servants, slaves to sin and Satan.

Rom 3:9  What then? are we better than they? No, in no wise: for we have before proved both Jews and Gentiles, that they are all under sin;

Rom 5:12  Wherefore, as by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned:

Apostle Paul adds,

Eph 2:1  And you hath he quickened, who were dead in trespasses and sins;
Eph 2:2  Wherein in time past ye walked according to the course of this world, according to the prince of the power of the air, the spirit that now worketh in the children of disobedience:
Eph 2:3  Among whom also we all had our conversation in times past in the lusts of our flesh, fulfilling the desires of the flesh and of the mind; and were by nature the children of wrath, even as others.

When we are slaves, under Satan, we are controlled and limited, spiritually immature children who are all in bondage to the foundational principles and elements of this world.

Then He called us in the church of God, and Jesus Christ became our redeemer. How? He became the atoning sacrifice that bridges the gap, caused by sin. Christ became the curse of the law, the penalty of death, for us and redeemed us fromSatan and from sin’s grasp so that we could begin to have a relationship with our Father, the Creator and God.

Those who responded on God’s calling were given the opportunity and the right to become His sons and daughters.

Joh 1:12 But as many as received him, to them gave he power to become the sons of God, even to them that believe on his name:
Joh 1:13  Which were born, not of blood, nor of the will of the flesh, nor of the will of man, but of God.

So, this calling is symbolized by adoption. As we all know, when we are not called yet, we had a father- a being whose image we bore, whose deeds we followed and whose words we spoke. It was this father that enslaved us and it was his system that we all willingly participated in before God’s intervention.

It was this system that the Galatians were returning to and which Paul was speaking against (Galatians 4:3, 8-11).

Gal 4:3  Even so we, when we were children, were in bondage under the elements of the world:

Gal 4:8  Howbeit then, when ye knew not God, ye did service unto them which by nature are no gods.

Gal 4:9  But now, after that ye have known God, or rather are known of God, how turn ye again to the weak and beggarly elements, whereunto ye desire again to be in bondage?

Gal 4:10  Ye observe days, and months, and times, and years.

Gal 4:11  I am afraid of you, lest I have bestowed upon you labour in vain.

Because of the price that Christ paid, God purchased those individuals that He has a plan for, and thus they became His “adopted” sons and heirs—but not yet inheritors—to the promises made to Abraham and to the Kingdom.

Gal 3:29  And if ye be Christ’s, then are ye Abraham’s seed, and heirs according to the promise.