1.Cor5,1 It is actually reported that there is sexual immorality among you, and of a kind that does not occur even among pagans: A man has his father's wife. 2 And you are proud!  Shouldn't you rather have been filled with grief and have put out of your fellowship the man who did this? 
1.Cor5,3 Even though I am not physically present, I am with you in spirit. And I have already passed judgment on the one who did this, just as if I were present.
> Don't know what he wants to say/ .... ? > !
4 When you are assembled in the name of our Lord Jesus and I am with you in spirit, and the power of our Lord Jesus is present, > And the power of the Lord is present. 
When we are together -> Being together makes that!
 ---- in the name of the Lord -> When are we not assembled in the name of the Lord - ???
and the power of our Lord Jesus is present - HOW?
?
?
5 hand this man over to Satan, so that the sinful nature may be destroyed and his spirit saved on the day of the Lord. > The sinful nature may be destroyed - NOT THE MEN. Also again, what about the women. How ist the husband doing? Crazy - but we do not have much information. Paul is not talking about a lot of details...
6 Your boasting is not good. > When do i boast? Don't you know that a little yeast works through the whole batch of dough?  > So i little sin is effecting the hole group!
7 Get rid of the old yeast that you may be a new batch without yeast- as you really are. > AS YOU REALLY ARE. Paul reminds them what they still are. What they became through Christ. For Christ, our Passover lamb, has been sacrificed. > Because Christ died - was sacrificed!
8 Therefore let us keep the Festival, not with the old yeast, the yeast of malice and wickedness, but with bread without yeast, the bread of sincerity and truth. / 8 Darum lasst uns das Fest feiern, nicht mit altem Sauerteig, auch nicht mit Sauerteig der Bosheit und Schlechtigkeit, sondern mit Ungesäuertem der Lauterkeit und Wahrheit!
9 I have written to you in my letter not to associate with sexually immoral people- / 9 Ich habe euch in dem Brief geschrieben, nicht mit Unzüchtigen3 Umgang zu haben; 
10 not at all meaning the people of this world who are immoral, or the greedy and swindlers, or idolaters. In that case you would have to leave this world.
11 But now I am writing to you that you must not associate with anyone who calls himself a brother but is sexually immoral or greedy, an idolater or a slanderer, a drunkard or a swindler. With such a man do not even eat. / 11 Nun aber habe ich euch geschrieben, keinen Umgang zu haben, wenn jemand, der Bruder genannt wird, ein Unzüchtiger ist oder ein Habsüchtiger oder ein Götzendiener oder ein Lästerer oder ein Trunkenbold oder ein Räuber; mit einem solchen nicht einmal zu essen. > How is what:
sexually immoral
greedy
idolater
slanderer
drunkard
swindler
Do not even eat with him!
12 What business is it of mine to judge those outside the church? Are you not to judge those inside? > We have much troubles to except or in my case to understand this
13 God will judge those outside.
Expel the wicked man from among you. > Not just sexually immoral but greedy.....swindler

I see, that their is a hole other way of having fellowship - even that the power of our Lord Jesus Christ is present ...

I see the seriousness of this sins: sexually immoral, greedy, idolater, slanderer, drunkard, swindler

This is very important for our next Singles-Devo!