Jesus is saying, If you obey my teachings — if you believe what I say about myself, and my Father, and our work of salvation — you will never see death. You won’t experience death.
John 11:25–26. Jesus says to Martha at Lazarus’ grave: “I am the resurrection and the life. The one who believes in me will live even if he dies, and the one who lives and believes in me will never die.” Your body dies, but you live.