A psalm that helped me following the Paris atrocity

Having read the BBC account of last night’s terrorist attacks in Paris, I turned to my Bible and read my morning psalm, which happened to be Psalm 55. Here is a part of that Scripture:

Listen to my prayer, O God,
do not ignore my plea;
hear me and answer me.
My thoughts trouble me and I am distraught
because of what my enemy is saying,
because of the threats of the wicked;
for they bring down suffering on me
and assail me in their anger.

My heart is in anguish within me;
the terrors of death have fallen on me.
Fear and trembling have beset me;
horror has overwhelmed me.
I said, “Oh, that I had the wings of a dove!
I would fly away and be at rest.
I would flee far away
and stay in the desert;
I would hurry to my place of shelter,
far from the tempest and storm.”

Lord, confuse the wicked, confound their words,
for I see violence and strife in the city.
10 Day and night they prowl about on its walls;
malice and abuse are within it.
11 Destructive forces are at work in the city;
threats and lies never leave its streets.

22 Cast your cares on the Lord
and he will sustain you; he will never let
the righteous be shaken.
23 But you, God, will bring down the wicked
into the pit of decay;
the bloodthirsty and deceitful
will not live out half their days.

But as for me, I trust in you.

Lord, have mercy; Christ, have mercy.