The book of Isaiah is very Messianic. The well-known chapter 53 is a prophecy of the suffering Jesus went through for our sins, and is quoted in the New Testament. Isaiah also prophesied about the coming of a forerunner before the Messiah (Is 40:3-4). A forerunner would go before the arrival of a great man such as a king to announce his soon arrival so the people would be ready to receive him properly and not be caught by surprise (1Sam 8:11, 2Sam 15:1, 1Ki 1:5, Est 6:7-9). The coming of the Messiah was the most greatly anticipated event for the Jews, and they needed to be ready for the appearing of their great King. Even men from far away lands were looking for this great event (Mt 2:1-2). The forerunner God sent to fulfill Isaiah’s prophecy was John the baptizer (Lk 3). Part of the prophecy was that the way would be prepared for the Messiah by every mountain being laid low and every valley being exalted, the crooked places being made straight, and the rough places made smooth. This describes what would be done to the path the king would take as he approached. They did not have tarmac or asphalt. Their dirt roads would be affected by the elements. Potholes, bumps, rough places, and detours around washed out places would be common. Some places in the world today are familiar with what the prophet was describing would happen to the road. So the people were to prepare the way when the announcement that the king was coming soon went forth. When Jesus made what is called “the triumphal entry” into Jerusalem that Zechariah prophesied about (Zech 9:9), the people laid garments and palm branches in the way before Him to make the road smoother (Mt 21:1-9).
Jesus did not come to be a highway inspector. He is concerned about the condition of our hearts. John did not come before Him to tell people they needed to raise money for infrastructure improvements. He told them they needed to change the state of their hearts by repenting of their sins and being baptized. They were not spiritually ready for Jesus to appear, so God sent John first so they could be positioned to properly receive Him when He came. That is why when the hypocrites came out to where he was baptizing, he questioned them (Mt 3:7-12). Their hearts were not seeking change. Yet he even told them to repent.
One reason some people do not stay in church long is because they did not prepare the way for the Lord to come into their hearts. Mountains are high places of pride and self-will that need to be brought low. Valleys are areas of discouragement, depression, doubt, and thoughts of low worth that need to be filled in. Crooked places are areas of unbiblical morals and values that pervert us. They are self-justification rather than being justified by God. Rough places are areas we have been beat up by the world and sin and made harsh, unforgiving, biting, and uncouth. God does not need our fancy words, but neither does He want us to be crass and “rough around the edges” forever. He wants to polish off those rough places. We do not need to get perfect to receive the Lord. We do not get good to get God. We get God to get good. Yet we do need to go through the process of repentance and preparing. It would be better to spend time in repentance before being baptized than to hurry up before we are ready and rush into a commitment we were not really prepared to make. We get in too big a hurry sometimes to rush people through the process. It would be better to spend some time preparing the way for the entrance of the King, get it right, and make it last, than to rush through it and not last. In the parable of the sower, there was nothing wrong with the seed. The problem was that the ground (our hearts) was not properly prepared to receive the seed (Mt 13:19-23). Either it was packed down too hard so the seed could not get in, it was too shallow so the seed could not take root, or it was filled with thorns that choked the seed. The ground could have been tilled and cleared of stones and weeds. It could have produced if it had been prepared properly.
After we are saved, God continually leads us to deeper places of relationship and ministry. We need to continue the process of preparing ourselves for what God has planned for us. We must never rest on our past and plateau. A Christian must always be in the process of preparation for future blessing. Sometimes it takes years, but we must always keep doing what we know to do until God leads us into something else. We never know when our day of visitation will come (Lk 19:44), and we never know when the Lord will return to take His bride. We must be prepared for His coming (Mt 25).