When Moses was a full forty years old he thought the Lord would deliver Israel by him. It made sense, Israel had been in Egypt for 390 years already. The time of the promise to Abraham (of 400 years) drew near. And what other Jew was in the position that Moses was in? Certainly everything came together neatly for the deliverance to take place in just 10 years. But however, after attempting to break up a fight between two brethren one said to Moses who made thee a deliverer and judge over us? And will you kill me as you killed the Egyptian? So Moses fled into the wilderness. The ten years passed. And many more years after that. Moses was wrong about the 400 year time frame. But how could that be? The answer is that God set it up for the Jews to misunderstand and to get the time of the deliverance wrong. Just look at how the Lord worded the promise to Abram:
Genesis 15:13-14 And he said unto Abram, Know of a surety that thy seed shall be a stranger in a land that is not theirs, and shall serve them; and they shall afflict them four hundred years; And also that nation, whom they shall serve, will I judge: and afterward shall they come out with great substance.
Moses knew about this promise as it would have been handed down and taught to all the Jews. We know Moses knew because of what we read in the book of Acts.
Acts 7:17 But when the time of the promise drew nigh, which God had sworn to Abraham, the people grew and multiplied in Egypt,
The context tells us that the time of the promise drew nigh. Then we read:
Acts 7:22-30 And Moses was learned in all the wisdom of the Egyptians, and was mighty in words and in deeds. And when he was full forty years old, it came into his heart to visit his brethren the children of Israel. And seeing one of them suffer wrong, he defended him, and avenged him that was oppressed, and smote the Egyptian: For he supposed his brethren would have understood how that God by his hand would deliver them: but they understood not. And the next day he shewed himself unto them as they strove, and would have set them at one again, saying, Sirs, ye are brethren; why do ye wrong one to another? But he that did his neighbour wrong thrust him away, saying, Who made thee a ruler and a judge over us? Wilt thou kill me, as thou diddest the Egyptian yesterday? Then fled Moses at this saying, and was a stranger in the land of Madian, where he begat two sons. And when forty years were expired, there appeared to him in the wilderness of mount Sina an angel of the Lord in a flame of fire in a bush.
Moses was 80 years old when God finally did use him as an instrument of deliverance to the Jews. Moses was 80 in the year 1447 BC. 1447 BC was 430 years from the time of Jacob and his family's entrance into Egypt in 1877 BC (1877 - 1447 =430). This means that forty years earlier when Moses was a full forty years old it was the year 1487 BC. And 1487 BC was 390 years from the time of Jacob and family's entrance into Egypt. Again, Moses knew the time line. The time of the promise was drawing nigh. Moses and probably all the learned Jews thought that the promise was 400 years. After all, that's what God specifically said in Genesis 15:13 "...thy seed shall be a stranger in a land that is not theirs, and shall serve them; and they shall afflict them four hundred years".
Oh, but God very carefully worded His statement to Abram. God did not say that Abram's seed would be a stranger in a land not theirs for four hundred years; no. Instead God said that "they shall afflict them four hundred years". That is the time of the affliction of Abram's seed in Egypt would be 400 years; not the total length of time for their stay there.
What's the difference? Well, when Jacob and his family first entered into Egypt they were cared for by Joseph. Joseph the 2nd in command in all Egypt. Joseph that had shown himself extremely wise and through him the Pharaoh was obtaining great riches and tremendous power. Certainly no one dare afflict the family of Joseph. At least not for a while. Not until Joseph's power waned; and not until probably that Pharaoh that had so benefited from Joseph's wisdom left the throne.
According to the Bible then, the affliction of Israel (Abram's seed) began 30 years after entering into Egypt. It did not have to be severe at first. It probably began subtly. Two men going for a job, one an Egyptian and the other a Jew. And the Egyptian getting the job even though the Jewish man was far better qualified. And slowly, over the years the affliction increased to the point of cruel bondage.
But the point is that Moses and the Israelites had a verse (Genesis 15:13) that said 400 years. They trusted that verse. Moses trusted it to the point of even slaying an Egyptian and publicly showing that he was the deliverer. And yet, he had to flee Egypt. The time frame was not quite right. Does this mean that Moses was wrong to look at the promise given to Abram concerning the seed being afflicted for 400 years? Does it mean that Moses was totally off base and looking at the wrong thing in thinking that the time of the promise was drawing nigh? No. Actually, he was looking at exactly the verse he should have been looking at. The time line was correct. Only some clarification was necessary. And that clarification could only come AFTER the original stated time of 400 years had passed.
God's people in Israel, people like Moses, and Joshua, and a few others, would have been encouraging their fellow Jews. The bondage was so hard. The taskmasters so cruel. Oh continue to hope my friend in God, the time of the promised deliverance isdrawing close. God promised to Abram it would be 400 years. And the Jewish people being meticulous about these things would have known the time Jacob came into Egypt (such a dramatic event in the life of that family had to be recorded and handed down to the following generations). Therefore the Jews would have been openly hoping and looking forward to that 400th year. Jacob entered Egypt 1877 BC. 400 years later would be 1477 BC. That's the year. The people in cruel bondage would have been looking forward to that time with their excitement building.
But then 1477 BC came and nothing happened. It was the 400th year. God's people would have been troubled. They would have greatly wondered what had happened? We know God cannot lie, and we know that He promised to Abram to bring them out after being afflicted 400 years (of course the idea of being afflicted would have escaped them at first). Why didn't the LORD come and deliver us?
We can be sure it wouldn't have been very long at all, before others in the congregation of Israel, would have begun to mock and murmur about the 400 year time path. What happened? Where is this great God? What didn't He come? You said He would come and deliver us and He didn't.
But God's people, confused, and not quite sure why there weren't delivered exactly at the 400 year mark, still, would have kept looking to the Scriptures and trusting that God was true and faithful. There must be something that they did not properly understand. Well, we know that 40 years later God came to Moses and sent him back to Egypt to be that same deliverer that he had assumed he would be some 40 years earlier.
Were the Jews right to look to the Word of God and to a time path that spake of 400 years? Yes. Even though they did not understand everything about that Scripture they were indeed looking at precisely the right thing. They had many things correct but lacked only a few important details.
Were murmuring Jews correct that may have said after the 400 year mark was passed---ah, throw out that time line. You're trusting in the wrong thing. We can't know when we'll be delivered (thus becoming the spiritual fathers' of the no man knows crowd). Stop looking. No way. They were not correct. The people of God looking toward the promise to Abram were on the right track. God would soon send Moses and deliver His people in the year 1447 BC, exactly after 400 years of affliction in Egypt (and 430th year overall).
Exodus 3:7-10 And the LORD said, I have surely seen the affliction of my people which are in Egypt, and have heard their cry by reason of their taskmasters; for I know their sorrows; And I am come down to deliver them out of the hand of the Egyptians, and to bring them up out of that land unto a good land and a large, unto a land flowing with milk and honey; unto the place of the Canaanites, and the Hittites, and the Amorites, and the Perizzites, and the Hivites, and the Jebusites. Now therefore, behold, the cry of the children of Israel is come unto me: and I have also seen the oppression wherewith the Egyptians oppress them. Come now therefore, and I will send thee unto Pharaoh, that thou mayest bring forth my people the children of Israel out of Egypt.