Bread of affliction

I was reminded recently that the unleavened bread of the Passover is also referred to as the "bread of affliction."  What is the meaning of unleavened bread?

"...that the Lord's law may be in thy mouth..." (Exodus 13:9)

Does it mean that we are to be reminded of the necessity of both a kind of sternness and immediacy of the law as well as the admonition to consume it so it is integral to our being?  Returning to II Corinthians again, Saint Paul declares that our affliction is "light."  Recall this?  He also says,

"...we look not at the things which are seen, but at the things which are not seen..." (II Corinthian 4:18)

We have been observing and pondering how these common themes: comfort and affliction; things seen and unseen; science, nature, and the supernatural; presence and absence; and ultimately, the sovereignty of God, relate one to the other.