John Wesley on Exodus 15:2

Israel rejoiceth in God, as their strength, song, and salvation - Happy therefore the people whole God is the Lord: They are weak themselves, but he strengthens them, his grace is their strength: they are oft in sorrow, but in him they have comfort, he is their song: sin and death threaten them, but he is, and will be, their salvation. He is their fathers God - This they take notice of, because being conscious of their own unworthiness, they had reason to think that what God had now done for them was for their fathers sake, Deu 4:37.