Chapter 13

All first born, both man and beast, belongs to God.  His price?  The firstborn males were to be redeemed.  God did not require that all the firstborn become slaves in the temple or anything like that.  But they were his, and were to be redeemed.  The redemption was with a sacrificial lamb.  Yet another type of Jesus, who redeems us from eternal hell, which is the just penalty for our sins.  I really am having trouble though with how this ties to the work of Christ?

MSB says that since the 10th plague did not touch the firstborn of Israel - He spared them from it - it is fitting that the firstborn be set aside as special to God.  So perhaps there is not a "tie" with Jesus as the firstborn other than that he was Mary's firstborn, and therefore special, and consecrated to God.

Next the requirements of the Feast of Unleavened Bread are reiterated.  MSB emphasizes that the Exodus, the consecration of the firstborn, and the instruction about the Feast of Unleavened Bread all occur on the same day as the Exodus.  This is a very big day.  The promises about the land of Canaan are also restated here, with God telling them that the plan will continue in that land after His promises are fulfilled.  The Passover lamb was to be set aside on the 10th.  All of Israel was to kill the lamb on the 14th.  Then, from the 14th until the 21st, no leavening allowed.  On the seventh day, the 21st is the Feast of Unleavened Bread.  The Feast of Unleavened Bread is reiterated in more detail here than in Chapter 12.  It was to be on the seventh day of eating the unleavened bread. 

The Lord leads Israel with a pillar of cloud by day and a pillar of fire by night.  MSB gives some details about the possible routes argued as the way the people actually went.  He seems to favor the route through the Bitter Lakes region.  I found a map of that, and this is an area along the present day Suez Canal, well north of the Red Sea itself.  I'm not going to get bogged down on the actual geographical route at this time.  But there is more here if one were interested.