How does God keep His saints according to the sermon?

God keeps His saints primarily through His own name, as suggested in John 17:11, where Jesus prays for the keeping of the saints through the authority of God's name. This entails not just the assurance of salvation but also the active involvement of God's means of grace, such as faith, prayer, the preaching of the Word, and the gathering of believers in worship. These means are vital for spiritual nourishment and growth, keeping believers aligned with God’s purpose and maintaining their connection to the church community, which is divinely ordained.