All sin is imprisonment. That is the direct contrary of the notion that many people have. They say to themselves, 'Why should I be fettered and confined by these antiquated restrictions of a conventional morality? Why should I not break the bonds, and do as I like?' And they laugh at Christian people who recognise the limitations under which God's law has put them; and tell us that we are 'cold-blooded folks who live by rule,' and contrast their own broad 'emancipation from narrow prejudice.' But the reality is the other way. The man who does wrong is a slave in the measure in which he does it. If you want to find out--and mark this, you young people, who may be deceived by the false contrasts between the restraints of duty and the freedom of living a dissolute life--if you want to find out how utterly 'he that committeth sin is the slave of sin,' try to break it off, and you will find it out fast enough. We all know, alas! the impotence of the will when it comes to hand grips with some evil to which we have become habituated; and how we determine and determine, and try, and fail, and determine again, with no better result. We are the slaves of our own passions; and no man is free who is hindered by his lower self from doing that which his better self tells him he ought to do. The tempter comes to you, and says, 'Come and do this thing, just for once. You can leave off when you like, you know. There is no need to do it a second time.' And when you have done it, he changes his note, and says, 'Ah! you are in, and you cannot get out. You have done it once; and in my vocabulary once means twice, and once and twice mean _always_.' Insane people are sometimes tempted into a house of detention by being made to believe that it is a grand mansion, where they are just going to pay a flying visit, and can come away when they like. But once inside the walls, they never get past the lodge gates any more. The foolish birds do not know that there is lime on the twigs, and their little feet get fastened to the branch, and their wings flutter in vain. 'He that committeth sin is the slave of sin--shut up,' dungeoned, 'under sin.' But do not forget, either, the other metaphor in our text, in which the Apostle, with characteristic rapidity, and to the horror of rhetorical propriety, passes at once from the thought of a dungeon to the thought of an impending weight, and says, 'Shut up _under_ sin.'