Manna as scaffolding

The provision and rules relative to manna served as a training mechanism for the children of Israel. They learned to be strictly obedient. Gathering to much led to problems and failing to prepare for the sabbath led to problems. It was a daily reminder that the Lord was providing for them – and yet they murmured.

Notice that while only the firstborn males of the cattle were set aside for the Lord (sacrificed or redeemed through the sacrifice of something else) all firstborn children were set aside for the Lord, male and female, and redeemed through a sacrifice.