Because an angel would go down into the pool from time to time and stir up the water. Then the first one who got in after the water was stirred up recovered from whatever ailment he had. John 5:4 HCSB

Then Jesus replied, “I assure you: The Son is not able to do anything on His own, but only what He sees the Father doing. For whatever the Father does, the Son also does these things in the same way. 

And just as the Father raises the dead and gives them life, so the Son also gives life to anyone He wants to. The Father, in fact, judges no one but has given all judgment to the Son,”

‭‭John‬ ‭5:4, 19, 21-22‬ ‭HCSB‬‬

https://bible.com/bible/72/jhn.5.4-22.HCSB

Jesus is stirring the waters of His day? In the story of the man who was beside the pool Jesus had him carry his mat. The religious leaders did not like it but were outraged. Jesus then began to explain who he was to them and his true potential. 

Am I willing to be that follower of Jesus who will trouble the waters of my day or I'm I willing to settle and become a religious leader who will pour over the Bible but miss Jesus moving?

“You pore over the Scriptures because you think you have eternal life in them, yet they testify about Me. And you are not willing to come to Me so that you may have life.”

‭‭John‬ ‭5:39-40‬ ‭HCSB‬‬

https://bible.com/bible/72/jhn.5.39-40.HCSB

“Summoning the crowd along with His disciples, He said to them, “If anyone wants to be My follower, he must deny himself, take up his cross, and follow Me. For whoever wants to save his life will lose it, but whoever loses his life because of Me and the gospel will save it. For what does it benefit a man to gain the whole world yet lose his life? What can a man give in exchange for his life? For whoever is ashamed of Me and of My words in this adulterous and sinful generation, the Son of Man will also be ashamed of him when He comes in the glory of His Father with the holy angels.”

‭‭Mark‬ ‭8:34-38‬ ‭HCSB‬‬

https://bible.com/bible/72/mrk.8.38.HCSB