Here is a great thought from Martin Luther:
Christian faith has appeared to many an easy thing; nay, not a few even reckon it among the social virtues, as it were. And this they do because they have not made proof of it experimentally, and have never tasted of what efficacy it is. For it is not possible for any man to write well about it, or to understand well what is rightly written, who has not at some time tasted of its spirit under the pressure of tribulation. While he who has tasted of it, even to a very small extent, can never write, speak, think, or hear about it sufficiently. For it is a living fountain, springing up unto eternal life, as Christ calls it in the 4th chapter of John.
Now, though I cannot boast of my abundance, and though I know how poorly I am furnished, yet I hope that after having been vexed by various temptations I have attained some little drop of faith, and that I can speak of this matter, if not with more elegance, certainty with more solidity than those literal and too subtle disputants who have discoursed upon it without understanding their own words. That I may open, then, an easier way for the ignorant–for these alone I am trying to serve–I first lay down these two propositions concerning spiritual liberty and servitude.
A Christian man is the most free lord of all, and subject to none; a Christian man is the most dutiful servant of all, and subject to every one.
Although these statements appear contradictory, yet, when they are found together, they will be highly serviceable to my purpose. They are both statements of Paul himself, who says: Though I be free from all men, yet have I made myself servant to all( 1 Cor. 9:19) and Owe no man anything, but to love one another(Rom. 8:8). Now love is by its own nature dutiful and obedient to the beloved object. Thus even Christ, though Lord of all things, was yet made of a woman; made under the law; at once free and a servant; at once in the form of God and in the form of a servant.