John 10:22 Now it was the Feast of Dedication in Jerusalem, and it was winter. 23 And Jesus walked in the temple, in Solomon's porch. 24 Then the Jews surrounded Him and said to Him, "How long do You keep us in doubt? If You are the Christ, tell us plainly." 25 Jesus answered them, "I told you, and you do not believe. The works that I do in My Father's name, they bear witness of Me. 26 "But you do not believe, because you are not of My sheep, as I said to you. 27 "My sheep hear My voice, and I know them, and they follow Me. 28 "And I give them eternal life, and they shall never perish; neither shall anyone snatch them out of My hand.

In this famous section of Scripture Jesus, the Light of the World is walking around at the Feast of Lights. The Pharisees confront him and ask Him again, who are You, tell us plainly? They ask this like they don’t know, like He hasn’t already told them time and time again. They have seen the signs, they have heard His Words, and yet they WILL NOT believe. Jesus says that all the signs that He has done for His Father in Heaven prove He is God too and they will not believe because they aren’t His Sheep. You see in this section Divine Sovereignty and Human Responsibility. God calls people to be saved and they cannot be saved unless He draws them (Divine Sovereignty), yet God says we are all responsible because the Scriptures says whosoever will, let him come, whoever believes, etc (Human Responsibility). He tells them that they cannot hear Him because they aren’t His Sheep because His Sheep hear His voice and follow Him. Then He finally tells them that if we are saved we are eternally secure for all time. Romans 8:31-39 confirms this as do many other places in the Bible. It says whoever believes HAS eternal life. John 17:3 says eternal life is KNOWING the true God and Jesus whom He sent. Nobody is greater than Jesus and so no one can snatch them out of His Hand.