I was reading the Bible today and I came across the passage in Exodus. I had two thoughts. The first one is where Pharaoh claims that he does not know "The Lord". You serve the Lord most likely because you have had an encounter with Him. There are a lot of people in our world that do not believe in Christ, they have never had an encounter with Him. If or when you try and witness to your friends we can't become discouraged. It may take years, so do not give up!
The second thought is that the Lord's work is never easy. So far Moses had an encounter with God, God almost killed him, and now God is telling Moses to do his work, but then God turns around and basically tells Moses that this battle you will not win, because I am going to harden his heart.
We can never become discouraged doing God's work. We must always keep our eye on the end goal. Maybe when you started something out, it did not turn out the way you planned, but it turned out the way God wanted it. Moses never saw the promised land, but if it were not for him and his work, God's people may have never entered it.
Exodus 5:1-2, 7:1-3
"Afterward Moses and Aaron went to Pharaoh and said, "This is what the LORD, the God of Israel, says: 'Let my people go, so that they may hold a festival to me in the desert.' "
Pharaoh said, "Who is the LORD, that I should obey him and let Israel go? I do not know the LORD and I will not let Israel go."
Then the LORD said to Moses, "See, I have made you like God to Pharaoh, and your brother Aaron will be your prophet. You are to say everything I command you, and your brother Aaron is to tell Pharaoh to let the Israelites go out of his country. But I will harden Pharaoh's heart, and though I multiply my miraculous signs and wonders in Egypt"