Yours is the day, yours also the night;
you have established the heavenly lights and the sun.
You have fixed all the boundaries of the earth;
you have made summer and winter.
I only need to look at the world around me to know that God is wise and in control. Day and night continue. The sun rises and sets. The moon and stars still shine at night. The earth makes its yearly circuit around the sun and with each solar tour the seasons cycle through. Spring, summer, autumn, and winter all go through their ceaseless unchanging patterns. There is rain and bright sun, snow and wind, heat and cool, and clouds and sunshine.
Life goes on upon planet Earth just as God designed it to do and exactly how He has made it. All the tragedies and pain in the world of men (the theme repeated throughout Psalm 74) all must occur on the broader stage of a universe created by and controlled by God. The words of Asaph call us into perspective, that none of our experience is outside of God's sovereign care. He sees, He knows, He is in control.
Asaph wrote the words of this song of mourning after the destruction of the temple in Jerusalem. And with the house of God a smoldering ruin, confidence could still be had that a sovereign Creator Who governs the universe would deliver His people and hear their prayers. The God Who moves the stars in the heavens and keeps the earth in cosmic time with the seasons will never be caught off guard by any human action or atrocity. He is already always in action on our behalf.
Look to creation if your life seems chaotic. There you will find the wise God in control. And from there you can cultivate the faith to trust Him despite the human chaos. He is the God of day and night.