Yes, this verse is a big "proof text" for the eternal security crowd. When I was an Evangelical I used to quote it all the time. But I always overlooked this part of the verse:
"...they follow Me..." So, our spiritual security is predicated upon whether or not we are following Christ. And following Him entails receiving Him. [St. John 1:12] And how do we receive Him? We receive Him through the Holy Mysteries. Those who do not eat of His body and drink of His blood have no part of Him, and many disciples stopped following Our Lord when He taught this. [St. John 6:53-68] Thus, if we are in the Father's hand (i.e. baptized into His Church and availing ourselves of the Sacraments), then we are spiritually safe and secure. But if we are out of His hand (i.e. either outside of His Church or not participating within it), then we are prey for the devil who
"roams about like a roaring lion seeking someone to devour." [I Peter 5:8][I know that was more than you asked. Sorry.]
Selam
