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?
9 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
9 But now that you have come to know God, or rather to be known by God, how can you turn back again to the weak and worthless elementary principles of the world, whose slaves you want to be once more?
9 But now that you know the real God - or rather since God knows you - how can you possibly subject yourselves again to those paper tigers?
9 But now after you have known God, or rather are known by God, how is it that you turn again to the weak and beggarly elements, to which you desire again to be in bondage?
9 So now that you know God (or should I say, now that God knows you), why do you want to go back again and become slaves once more to the weak and useless spiritual principles of this world?
Matthew Henry's Commentary on Galatians 4:9
Commentary on Galatians 4:8-11
(Read Galatians 4:8-11)
The happy change whereby the Galatians were turned from idols to the living God, and through Christ had received the adoption of sons, was the effect of his free and rich grace; they were laid under the greater obligation to keep to the liberty wherewith he had made them free. All our knowledge of God begins on his part; we know him because we are known of him. Though our religion forbids idolatry, yet many practise spiritual idolatry in their hearts. For what a man loves most, and cares most for, that is his god: some have their riches for their god, some their pleasures, and some their lusts. And many ignorantly worship a god of their own making; a god made all of mercy and no justice. For they persuade themselves that there is mercy for them with God, though they repent not, but go on in their sins. It is possible for those who have made great professions of religion, to be afterwards drawn aside from purity and simplicity. And the more mercy God has shown, in bringing any to know the gospel, and the liberties and privileges of it, the greater their sin and folly in suffering themselves to be deprived of them. Hence all who are members of the outward church should learn to fear and to suspect themselves. We must not be content because we have some good things in ourselves. Paul fears lest his labour is in vain, yet he still labours; and thus to do, whatever follows, is true wisdom and the fear of God. This every man must remember in his place and calling.