God is a perfect heavenly father and so he always forgives...and punishes as well. Consider God's fatherhood of Israel. "O LORD our God, you answered them; you were to Israel a forgiving God, though you punished their misdeeds" (Psalm 99:8 NIV).
God always forgave Israel, in fact he died for all of them as well as us. However, he also punished them and sometimes quite severely. Korah rebelled against Moses and so God swallowed Korah and his family alive into hole in the ground. Moses also rebelled against God's direction and struck the rock and therefore was not permitted into the promised land. David committed adultery with Bathsheba and murdered Uriah to hide it and so God took the life of Bathsheba's child and told David that the sword and trouble would never leave his household. The nation of Israel forsook the Lord for idols and so God sent the wicked nations of Assyria and Babylon to punish them. Jesus even prophesied the destruction of Jerusalem and the temple because Israel rejected him, and in 70 AD Rome leveled Jerusalem to dust.
Some would blind their eyes in dread fear of this God and say, "That was the Old Testament God. Jesus wouldn't do that!" The problem for them is that Jesus is the Old Testament God. Even in the New Testament dispensation under the New Covenant we see Jesus forgiving... and punishing. For example, the Christians Ananias and Sapphira, a husband and wife, agreed to partner in lying to the Holy Spirit and God immediately took their lives. God is a perfect father and so all these people were forgiven, yet not unpunished.
You may be aghast to consider that God did these things. Your faith may still be bubbling with the good news that Christ has forever forgiven your sin, just as it should be! However, in the midst of our excitement we must not neglect that we have terribly important work to do. Because we have received forgiveness, Christ has joined us to his ministry of forgiveness and... his ministry of discipline toward yet others!
In Luke 6 we are commanded "Do not judge...forgive." We should not condemn one another because of sin, but seek opportunity to forgive one another. In 1 Corinthians 5 we are also commanded to "judge those inside (the church)." Though we are not to condemn each other, believers are commanded to identify sin, correct, and reprove one another. The world's ideal is "live and let live," but such is not the true love between believers.
Sin is destructive and so true love demands that we lovingly invade one another's lives so that all may finish the race without shame. How are we to discipline one another when rebellion remains? God himself maintains the authority to punish with trial, sickness, and even death under the New Covenant just as he did the under the Old Covenant. Under the Old Covenant God also commanded Israel to punish rebels by death. However, now, under the New Covenant, believers are commanded not to kill, but to disassociate with anyone calling themselves a Christian who is following an immoral life.
Please do invite your unbelieving neighbor into your house to share Christ with him, even if he is a drunkard or any type of sinner. However, disassociate with anyone claiming to be a Christian who is immoral or a drunkard. Do this so that he may realize the gravity of his sin and perhaps be saved from self-destruction, and also so that others are not led astray by his rebellion. May this doctrine keep us close to the grace of Christ where abundant forgiveness and power over sin can be found. But don't take it from me, study 1 Corinthians 5 for yourself for God's pure word unadulterated by my ravings.