Exodus 8:22 & 23

"'"But on that day I will deal differently with the land of Goshen, where my people live; no swarms of flies will be there, so that you will know that I, the Lord, am in this land. I will make a distinction between my people and your people. This sign will occur tomorrow."'" NIV translation

Until this point, the plagues had affected all of the people in the land of Egypt. Now, God is going to protect His people so that the Egyptians see that he is in control. This is also a picture of the sealing of the witnesses as described in Revelation.

Exodus 8:24

"And the Lord did this. Dense swarms of flies poured into Pharaoh's palace and into the houses of his officials; throughout Egypt the land was ruined by the flies." NIV translation

God sent the beetles and their so-called sacred thing became a curse. This is a reminder to us that those who put their hope in the things of the world will be cursed by those things. 

Exodus 8:25

"Then Pharaoh summoned Moses and Aaron and said, 'Go, sacrifice to your God here in the land.'" NIV translation

Once again, Pharaoh tries to get Moses and Aaron to compromise in what God had said to them. This is the way that Satan works in the world today. That compromise can cause separation as we know that it is wrong. Satan can then use that separation to make us feel that we are unable to turn back to our heavenly Father.