The questions David asks are similar to those asked by many believers when they are experiencing difficulties. Is God present? Is there a reason why He is not intervening today? Whenever life goes smoothly, it is easy to praise the Lord but harder when difficulties arise. As we are uncertain or uneasy, faith can reassure us by looking back on what we know about God.
Although we may not understand all that God has planned and proposed, He has appointed a time for the wicked to be judged. In spite of the atrocities taking place today, God has appointed a day for the completion of transgressions, the eradication of sin, the atonement for wickedness, and the establishment of everlasting righteousness, placing His King on His holy hill in Jerusalem.
The grace of God has been pouring out for two thousand years, not wanting anyone to perish. But the day will come when wicked and evil men will be held accountable for their actions. We are approaching a day of wrath when the nations will be judged, and we will see God wipe away every tear from our eyes.

Dear Heavenly Father, You know what humble people hope for. Your help will comfort their hearts and hear their cries. I put my trust in You that Your will will be done and You will not delay. My thoughts go out to my brothers and sisters suffering across the globe. Let Your hand rise, Lord. Let Your people be delivered quickly by hearing their cries. 
In Jesus's name I pray. Amen.