1 Peter 5:7 (ESV) … “casting all your anxieties on him, because he cares for you.”
As we trust God and his mighty power, we follow a God who cares deeply for us. Peter may have had in mind the words of Jesus (Matt. 6:25–34). If so, he borrowed them and placed them in the context and crucible of suffering and persecution.
Cast means “to throw something upon someone or something else.” This word suggests a deliberate decision of trust. We are to trust God with our anxiety, the things we worry about. The term (merimnan) means “to be drawn in different directions, to be divided or distracted.”
Whatever we are anxious about tends to distract us from trusting God. It tends to pull us in different directions so that we do not depend on him. When we limp in this direction, we do not resist Satan, but play into his hand. He wants us to put more trust in ourselves and others as opposed to God.
Peter’s first-century readers, like their twentieth-century cousins, failed to remember this truth even in the midst of anguish and pain: God cares for you. The form in which the verb appears (present active indicative with the dative) indicates that God’s care and concern for believers is constant, ongoing, and unending. 
What is to be made of this verse? That God is not indifferent to the suffering of his followers, but desires our active, humble trust in him, especially during difficult days. Difficult days will come in life, but we must trust in the Lord. Therefore, we must cast all our anxieties on him, because he cares for us!