Even though Israel knew, committed themselves, and repented, they still succumbed to rebelliousness to God; there is no question that we also suffer from the same short-term dedication sometimes in our lives.
Israel's clear defiance and lack of faith caused them years of wandering in the wilderness accompanied with a multitude of lessons; we face and deal with the same issues if we wander from God in life.
When Jacob wrestled with God, he had the stark realization that he needed to yield and recognize the Almighty; our struggles should bring us to the same reality.
Israel was a nation without a country, and they wandered in the wilderness for many years as they tried to go home; Christians are also sojourners living on this world while awaiting their real home.
Even after being delivered by God from Egypt, Israel continued to grumble and complain; we have the same struggle as Christians as we often look at ourselves instead of recognizing God.