Numbers 28:23 - Joseph Benson’s Commentary on the Old and New Testaments

In the morning And that in the evening too, as is evident from other passages of Scripture. But the morning sacrifice alone is mentioned, both because the celebration of the feast began with it, and because this alone was doubtful whether this might not be omitted, when so many other sacrifices were offered in that morning: whereas, there was no question but the evening sacrifice should be offered, when there were none other to be offered. This solemn festival was designed as an acknowledgment of God's goodness in bringing them out of Egypt, and making them a free people; which was the foundation of all their future blessings.