What does the Bible say about Christ preserving His disciples?

In John 6, Jesus emphasizes the security of His disciples by stating that all those given to Him by the Father will come to Him, and He will not cast them out (John 6:37). This preservation reflects God's sovereign grace, as He ensures that those whom He has chosen will ultimately persevere in faith until the end. The assurance that true believers cannot fall away is central to historic Reformed theology, aligned with passages like John 10:28-29, which declare that no one can snatch Christ’s sheep out of His hand.