To cast something means to throw it away from yourself.
You can throw whatever burdens you have to the Lord
and He will carry the weight of them for you.
He will hold and support you;
He will not let you be tossed around.
Are you holding tightly to something that is heavy or painful?
Will you throw it to the Lord and let Him carry the weight?
Blessings this day of grace,
My mantra on this is: Let go and Let God.
Very wise, seeker.