Psalm 54:4 is good for anyone going through trying times. It gives hope when we feel helpless. I like the use of the word surely here. There is a confidence and a certainty about it. God WILL BE my help. There is no doubt about it.
I also like the fact that this verse does not stop with the help. It assures us of the Lord sustaining us. There is help for the long haul, not just for now. There is a future plan that God has in place to keep us going in our faith and in our life with him. There is no end to the care that our Lord provides for us. Even unto eternity, he sustains us by taking us to heaven with him when we die.
His help and sustaining are ever-present and ever-giving. We are never in this life alone with our Great Sustainer beside us.