Here is some more on the Morning Watch, from Newman Sze:
Morning is the time God set for meeting His children and distributing spiritual food to them. Why is it a great blessing for the Christian to rise early in the morning and come to God? It is because morning is the time we present ourselves before God, and it is also the best time to have fellowship with Him. During the time of the Old Testament, it was in the morning that the Israelites got up to collect the manna. After sunrise, the manna would melt away.
In the same way, God provided that every morning should be the time to distribute spiritual food to His children, and the time for them to have holy and pure fellowship with God. Whoever came late would not be able to get the food or fellowship that they needed. How you behave in the morning watch will dictate your spiritual condition of the whole day. It is really unalterable as a rule, especially for those who have just begun to follow God.