Jesus answered them, “I told you, and you do not believe. The works that I do in my Father’s name bear witness about me, but you do not believe because you are not part of my flock. My sheep hear my voice, and I know them, and they follow me. I give them eternal life, and they will never perish, and no one will snatch them out of my hand. My Father, who has given them to me, is greater than all, and no one is able to snatch them out of the Father’s hand. I and the Father are one.” John 10:25–30, ESV
God is Sovereign. That sovereignty is not partial. It is not subject to any conditions or forces outside of God. He has never nor will He ever relinquish any portion of His sovereignty. What He sets out to do, He does. What Men believe or refuse to believe about these truths changes nothing. Just because professing Christians cling to the fallacy that they are saved because they exercised their Free Will does not in any way diminish the truth from God’s Word that tells us the very opposite.
Man is fallen. All born of Adam are children of God’s wrath. No one seeks after God because none are righteous (Romans 3:10–18). God’s people are part of our Lord’s flock. Those of His flock believe God, seek God, and know the Lord’s voice. The Lord gives them eternal life. Notice that the veracity of their eternal life is not subject to them or their behavior. No, the Son holds them and no one can snatch them out of His hand.