Expel Immoral People

1 Corinthians 5:9-13
"I wrote to you in my epistle not to keep company with sexually immoral people. 10 Yet I certainly did not mean with the sexually immoral people of this world, or with the covetous, or extortioners, or idolaters, since then you would need to go out of the world. 11 But now I have written to you not to keep company with anyone named a brother, who is sexually immoral, or covetous, or an idolater, or a reviler, or a drunkard, or an extortioner—not even to eat with such a person. 12 For what have I to do with judging those also who are outside? Do you not judge those who are inside? 13 But those who are outside God judges. Therefore “put away from yourselves the evil person.”

These are harsh words of judgement, black and white, cut and dry. God's church is to be holy. A little leaven (sin) leavens (contaminates) the whole lump of dough. I understand the principle here and the purpose behind it, but how can we really practice this? Where do we draw the line with covetousness? How much reviling is too much? How many times must a brother get drunk? Is the principle limited to these sins or do we expel the thief, liar and divider too? Once we throw them out into the world, are we allowed to associate with them again?
I suppose the only way to practice this principle is through prayer - asking God to help judge. After all, prayer is the central point in Matthew's 18th chapter on confronting a sinful brother.

Matthew 18:18-20 "Assuredly, I say to you, whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven. 19 “Again I say[c] to you that if two of you agree on earth concerning anything that they ask, it will be done for them by My Father in heaven. 20 For where two or three are gathered together in My name, I am there in the midst of them.”

Prayer is what turns a sinner around and brings restoration. It also advises that if a brother must be expelled, treat him as a pagan, a tax collector or sinner... which would open up a whole new door of relationship and opportunity again. But can I then have a meal with him?

God - make me pray more. May my judgements come from You and not from within me. When you judge, give me words to speak and strength to act. Make me the protector of your church and the children you have entrusted to me. Amen.