I have always been fascinated by the Passover and how it set the stage for Jesus. The Lord warned the Egyptians about what would happen if they rebelled against Him. He told the Israelites exactly what to do so that they would be saved. The Israelites took God at His Word, and kept His commands concerning the Passover. The men of the homes marked the lentils and posts of their doors with the blood of the Passover lamb. Then, they went inside to their wives and children. They probably got the kids ready for bed and kissed them as they settled in for the night. I imagine the Israelite fathers probably looked again at their firstborn that night, and thanked the Lord for His Word that He would "not allow the destroyer to come in to" the homes of those who had the blood on the lentil and the doorposts.
It is important to understand that in that night, God did not spare those Egyptians who rejected Him, but served the Egyptian gods sincerely and with good intention. In the same way, The one Lord of the universe provided His Son as our Passover Lamb, once and for all. No one who rebels against God and makes Him out to be a liar will be spared His judgment. Many people, even in "Christian" churches hold the belief that the Lord just asks that we believe in any god and serve faithfully. The Word of God has made no such allowance. To do so would render the sacrifice of His Son empty. Man's depraved mind chooses to believe that it is merciful to move the truth to accommodate man's preferences, rather than to move the heart of man to accommodate the truth.
Gentlemen, that kind of "mercy" will lead to destruction. Let me tell you about mercy. Mercy is found in the heart of the Lord of the universe who sent His Son to work salvation for a world that did not acknowledge Him. Mercy is found in the heart of the One God who gave His Word and created everything that exists to teach us about Himself so that we could know Him. Mercy is found in the heart of the Shepherd who leaves the ninety-nine sheep safe on the mountain and goes to find the one that is lost.