This wise saying discusses two different characters – “the person of integrity” and “the sinner.” In both cases their character leads to some specific outcomes in their lives.
A “person of integrity” is someone committed to making good decisions. It’s more about thinking than doing!
Of course, this doesn’t mean they are perfect. But such attitudes on a daily basis set them up for some good results – “righteousness guards” them regularly.
On the other hand, “the sinner” is a rather opposite character. “Wickedness overthrows” them.
Because of their own lifestyle choices, it could be their own wickedness or the wickedness of others. Either way, the result is the same – it “overthrows” or turns their world upside down.
This is the kind of things we attempt to teach our children from their earliest days – there are benefits or consequences to our choices. It reminds us of another Biblical and popular wise saying, “we reap what we sow!”