This is in reference to Exodus 12:13:
...and when I see the blood, I will pass over you, and the plague shall not be upon you to destroy you, when I smite the land of Egypt.
And this action lead to this testimony:
Exodus 15:13
You in your mercy has led forth the people which you have redeemed.
And
Exodus 15:16
...the people...which you have purchased.
But these same individuals, that were redeemed, purchased, and covered by the blood, ended up like this after disobedience:
Numbers 14:
[27] How long shall I bear with this evil congregation...[30] Doubtless you shall not come into the land, concerning which I swore to make you dwell therein...[32] But as for you, your carcasses, they shall fall in this wilderness. ...[34] ...and you shall know my breach of promise.
Now take grave heed to this new testament passage that uses the very scriptures I just quoted in the old testament:
1 Corinthians 10:
[10] Neither murmur ye, as some of them murmured, and were destroyed of the destroyer. [11] Now all these things happened unto them for examples: and they are written for our admonition...[12] Wherefore let him that thinks he stands take heed lest he fall.