What is "treasure in heaven"?, page-73

RM, there was a way to avoid the effects of the tenth plague.
21 Then Moses summoned all the elders of Israel and said to them, “Go at once and select the animals for your families and slaughter the Passover lamb. 22 Take a bunch of hyssop, dip it into the blood in the basin and put some of the blood on the top and on both sides of the doorframe. None of you shall go out of the door of your house until morning. 23 When the Lord goes through the land to strike down the Egyptians, he will see the blood on the top and sides of the doorframe and will pass over that doorway, and he will not permit the destroyer to enter your houses and strike you down.
How do we know that some of the Egyptians were obedient to the command.

37 The Israelites journeyed from Rameses to Sukkoth. There were about six hundred thousand men on foot, besides women and children. 38 Many other people went up with them, and also large droves of livestock, both flocks and herds. 39 With the dough the Israelites had brought from Egypt, they baked loaves of unleavened bread. The dough was without yeast because they had been driven out of Egypt and did not have time to prepare food for themselves.

Verse 38 says many other people went up with them. Evidently others besides the Israelites obeyed the command to splash the blood on the doorframe. They put faith in the words of Moses and so escaped the tenth plague, and left Egypt with the Israelites.

Pharaoh brought this calamity on his own people. A warning was given. Those who acted in faith were saved. This theme of obedience is carried through the entire Bible. A valuable lesson even in our day.