Psalm 19 is one of glory for God. It begins first by talking about His creating of the universe, then of His perfect law and what it does for those who follow it in verses 7-10.

Ignorance of the bible is something we face quite frequently. People taking verses out of context and changing them to mean all matter of things. 

Let's consider two different types of mourning.

[Zephaniah 1: 14-16]

The great day of the Lord is near; It is near and hastens quickly. The noise of the day of the Lord is bitter; There the mighty men shall cry out.
That day is a day of wrath, A day of trouble and distress, A day of devastation and desolation, A day of darkness and gloominess, A day of clouds and thick darkness, A day of trumpet and alarm Against the fortified cities And against the high towers.