You are either under grace or your are under wrath. Jesus is coming in wrath. God never pours out His wrath without warning. God is obligated by His character to warn. Therefore, God is obligated to let us know the season of the Lord's return.
Now, how can we know it? God wants us to know it, but how does He reveal it? He reveals it through signs — through signs that we are to watch for. The same principle applied to the First Coming of Jesus.
In Matthew 16 you will see this principle. In verse 1 we find Jesus teaching when He is suddenly confronted by the Sadducees and Pharisees. Here are the religious leaders of Israel demanding a "sign" to prove that Jesus is the Messiah. They want Him to perform a miracle. He says, "I don't understand you guys. You can look at the sky and tell what the weather is going to be, and you can't look at me and discern the signs of the times? What miracle do you need? What sign do you need besides what I'm doing?"
What's Jesus referring to? He's referring to the fact that the Hebrew Scriptures, which these men had been studying all their lives, contain over 300 hundred prophecies about the First Coming of the Messiah. Many of those prophecies are repetitious. If you boil them all down you'll come out with about 109 separate and distinct prophecies about the First Coming of Jesus. These prophecies foretold everything about His life — where He would be born, how He would be born, that He would go into Egypt, that He would live in Galilee, that He would heal people and love people. All aspects of His ministry were prophesied.
Take Jesus' lineage for example. It was prophesied that He would be descended from Abraham and Isaac and Jacob and David. The last days and hours of His life were prophesied in incredible detail. The prophets said He would be betrayed, by a friend, for 30 pieces of silver, that He would be lifted up, and that He would be pierced in the side and in His hands and feet. Every aspect of His life and death was prophesied.
Now, Jesus is fulfilling all those prophecies before the very eyes of the Scribes and Pharisees. Yet, they are demanding a "sign!" So Jesus replies, "How blind can you be? I'm fulfilling the signs of the times."
Now folks, here's the point: There are 300 hundred prophecies about the First Coming of Jesus in the Old Testament, but there are 500 — five hundred! — in the Old Testament about His Second Coming! And in the New Testament, one out of every 25 verses has to do with the Second Coming of Jesus. In other words, there are many, many, many more prophecies about the Second Coming of Jesus than His First Coming. Probably twice as many. Why so many? Because Jesus is returning in wrath. The first time He came, He came as a compassionate Savior with tears in His eyes. But when He returns, He is returning as a conquering warrior with eyes like white hot flames because He is returning to judge and make war against the enemies of God.
And so, since God does not wish that any should perish, He has given us sign after sign after sign to watch out for Jesus' return.