They were filled with all manner of unrighteousness, evil, covetousness, malice. They are full of envy, murder, strife, deceit, maliciousness. They are gossips, (ESV)
What happens when you remove God from a society? It ought to frighten you. Paul is continuing to describe mankind. God has revealed himself to mankind. Man did not "see fit to acknowledge God," so He gave mankind over to a debased mind, to do what ought not to be done. In verses 29 and 30 he gives a partial list of what we can expect from a godless society.
This list given to us in verse 29 is harrowing. All manner of unrighteousness. If you can think of some terrible kind of evil, be sure that someone has already done it or is planning it. We have simply to look back at the history of atheistic nations and consider the atrocities. China, Soviet Union, Nazi Germany are responsible for the ruthless murder of millions upon millions of people.
Those who refuse to be filled with the goodness of God will be filled with all manner of unrighteousness. Out of that cesspool of depravity we get all of the terrible things mentioned in this verse. I find it interesting that within this list is the sin of gossip. Gossip seems to be that sin that goes on even in the church and we do nothing about it. It has its source in the same pile of spiritual filth as murder.
As you slowly read through this verse you may find yourself thinking that these qualities are only found in the worst of mankind. I have bad news for you. Whether we have done these things or not our heart is just as wicked as if we did. Jesus came and taught the Jews that we can say we are not murderers but if we hate our brother we might as well be. The heart of mankind is evil. Even yours.
This are sobering words. Consider just how evil sin is. Look to the Savior. Ask him to forgive your sin and to continue to show you areas of darkness within that need more of his purifying light.