Galatians 4:7

Art - "Are"; second person singular.

Wherefore - Why?; for what reason?; for what cause?

Thou art no more a servant - Thou who hast believed in Christ art no longer a slave, either under the dominion of sin or under obligation to the Mosaic ritual; but a son of God, adopted into the heavenly family.

And if a son, then an heir - Having a right to the inheritance, because one of the family, for none can inherit but the children; but this heirship is the most extraordinary of all: it is not an heirship of any tangible possession, either in heaven or earth; it is not to possess a part or even the whole of either, it is to possess Him who made all things; not God's works, but God himself: heirs of God through Christ.

Wherefore - In consequence of this privilege of addressing God as your Father.

Thou art no more - You who are Christians.

A servant - In the servitude of sin; or treated as a servant by being bound under the oppressive rites and ceremonies of the Law; compare the note at Galatians 4:3

But a son - A child of God, adopted into his family, and to be treated as a son.

And if a son ... - Entitled to all the privileges of a son, and of course to be regarded as an heir through the Redeemer, and with him. See the sentiment here expressed explained in the the note at Romans 8:17.

4:7 Wherefore thou - Who believest in Christ. Art no more a servant - Like those who are under the law. But a son - Of mature age. And if a son, then an heir of all the promises, and of the all - sufficient God himself.