As David presses on in his prayer to God to protect David from his looming enemies David points out some of the wicked things that his enemies are up to and just generally wicked attributes of uncaring people

Psa 17:10  They have closed their unfeeling heart, With their mouth they speak proudly.

“They have closed their unfeeling heart” – this implies the wicked lack compassion or mercy.  So while the righteous have empathy, we see today that the wicked do not, they are hard hearted.  

Also the wicked like to boast, as outlined in today’s passage “with their mouth they speak proudly” in the wicked person’s own foolish minds they are their own gods, and boasting is basically self-worship, so rather than praise God, the wicked prefers to praise themselves.  

Social media can be a dangerous place for this type of stuff, the most viral posts and the hottest takes are usually full of self worship, “look at me, look at how great I am, look at what cool stuff I have”, all of that is based on boasting or self worship and as today’s Word tells us, it is the same thing that wicked people do.  In other words, sinful behavior that we as Christians are to avoid.