11 God is a righteous judge,
And a God who is indignant every day.

And we often think He pays no mind; that He overlooks the rampant, unending evil done one against another every day.  

12 If a man does not repent, God will sharpen His sword;
He has strung and bent His [mighty] bow and made it ready.
13 He has also prepared [other] deadly weapons for Himself;
He makes His arrows fiery shafts [aimed at the unrepentant].

This is not the GOD we like to present these days. We present a GOD that is grandfatherly; one that closes His eyes and says oh that’s okay, no repentance is necessary, everyone is welcome.  
Everyone is welcome, welcome to repent and live. 

14 Behold, the [wicked and irreverent] man is pregnant with sin,
And he conceives mischief and gives birth to lies.

Commentary will be limited here – look around. See. 

15 He has dug a pit and hollowed it out,
And has fallen into the [very] pit which he made [as a trap].
16 His mischief will return on his own head,
And his violence will come down on the top of his head [like loose dirt].

This is inevitable for those who do not repent. It’s not what GOD wants but unbending, unrepentant, obstinate mankind leaves Him no choice but to allow sin to complete its work. 

17 I will give thanks to the Lord according to His righteousness and justice,
And I will sing praise to the name of the Lord Most High.   source

But the saved. We have every reason to give thanks and rejoice, even while we pray for others. We rejoice not at their destination or destiny but we are certainly grateful for our own in JESUS THE CHRIST.