Isaiah’s words are part of a song of thanksgiving. God’s people praise the Lord because he has saved them. Remembering what God has done gives them courage to trust him with what lies ahead.
Notice that the verse says the Lord himself is our strength. Our deepest help comes through our relationship with him. We do not have to carry every burden by ourselves.
Calling God our savior means recognizing that we need his saving love. In Jesus, that love enters our human suffering, bears the Cross, and opens the way through death to risen life.
Faith does not require us to feel strong all the time. Sometimes trusting God means admitting, “I am tired. I am afraid. I need help.”
The courage God gives is often enough for the next faithful step, even when we cannot yet see the whole path.