We should not fear anything if God is with us, He is our protector and who helps us overcome everything that wars us. That is why we should only trust in God who is our helper.
The psalmist David was giving thanks for the goodness of God towards him, since the Lord delivered him from the clutches of his enemies. There were many who wanted David’s death because they knew that God was always with him, and that He never left him alone.
The mercy of God was always on David, and every day his strength and knowledge was increased because this man knew how to thank God with his heart and soul.