They soon forgat his works; literally, they hasted and forgat his works. Their gratitude and devotion were short-lived. They almost immediately forgot the omnipotence and extreme goodness of God towards them.
They "murmured" at Marah (Exodus 15:24), complained in the wilderness of Sin (Exodus 16:3), "lusted" (Numbers 11:4), "tempted God," etc. They waited not for his counsel; i.e. "they did not wait for the development of God's plans respecting them, preferring (Psalms 106:43) their own counsel" (Kay).