There's an incredible promise in 1 Peter 5: Cast all your anxiety (worries, cares) upon Him because He cares for you. That command (to cast worry upon God) is predicated on His character (He's a caring God) and His disposition toward me (He cares for me).
I've sat in offices and at lunch tables trying to help people understand that command as they walk through overwhelming and awful circumstances. I have tried to help them see that it's a command we have to obey often throughout the day when emotions are fragile and darkness sets in, not just a one-time-here-it-is-God obedience. Continually, we have to cast our worries upon Him because they nag at us and haunt us.
I've struggled with painting a picture for them of what this looks like. I think I have a good biblical picture in King Hezekiah. At the midpoint of Isaiah's prophecy, Hezekiah is in bad shape. King Sennacherib from Assyria has invaded and is about ready to lay siege to Jerusalem in full force. Hezekiah and his advisors pray and then receive word from the Lord through Isaiah that the Assyrian king will return to his own land and be killed. Sennacherib does return to Assyria, but writes a letter back saying Hezekiah better not get too comfortable because he's coming back to finish what he started.
I love Hezekiah's response: he goes to worship and lays the letter before the Lord in the temple (Isaiah 37.14ff). He offloads all the worry and concern, spreading the letter before the Lord. He knows he is not big enough to handle the Assyrian army or their threats but God certainly is.
What a great picture. We can lay anything and everything out before the Lord. That's how we cast our worries upon Him because He cares for us.