'Known' in the Bible

For I want you to know, believers, that the gospel which was preached by me is not man’s gospel [it is not a human invention, patterned after any human concept].

Now, however, since you have come to know [the true] God [through personal experience], or rather to be known by God, how is it that you are turning back again to the weak and worthless elemental principles [of religions and philosophies], to which you want to be enslaved all over again?