Can a person lose his or her salvation?

This text is from a transcript of a talk by David Gooding, entitled ‘God’s Glorious Plan for Creation’ (2007).

Well that's a very big question and some Christians hold one view and some another. I can tell you tonight what I hold and if you think that's unsatisfactory, come back and put another question to me tomorrow. But we read that Christ came as a shepherd of the sheep. He was talking to people who didn't accept him as a shepherd, the Pharisees, so he stood there and, if I may use the vulgar term, he 'advertised' himself as the shepherd, as a good shepherd indeed. Now what would you expect a good shepherd to do? He said, 'I am the good shepherd. The good shepherd lays down his life for the sheep' (John 10:11). That's one thing. Christ did that at Calvary. He's risen again now. Then he says,

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. (John 10:28–29)

This is the shepherd talking. He defies anybody to pluck his sheep out of his hand. I rest my case there: the shepherd won't lose any of his sheep.