My sheep hear my voice, and I know them, and they follow me: and I give unto them eternal life; and they shall never perish, neither shall any man pluck them out of my hand. My Father, which gave them me, is greater than all; and no man is able to pluck them out of my Father's hand. (John 10:27-29)
His sheep hear His voice, and they follow Him. The brand of ownership on the sheep is obedience. Do you want to know whether a person is saved or not? Then see if he is obeying Christ. Our ears must be open to His voice. "The hearing ear, and the seeing eye, the Lord hath made even both of them" (Proverbs 20:12).
"And they follow me." I believe in the eternal security of the believer and in the insecurity of the make-believer. If a shepherd called his sheep one morning and out of five hundred sheep in the sheepfold one hundred came out and followed him, then I would conclude that those one hundred were his sheep. And I would also conclude that the other four hundred were not his sheep.
"And I give unto them eternal life; and they shall never perish." Friend, when He gives to them eternal life, that means they don't earn it and they don't work for it. He gives it to them. Note that it is eternal life. It is forever. If it plays out in a week, or in a year, or until they sin, then it is not eternal life after all. They are not really His sheep if the life does not last forever. The sheep may be in danger, but the Shepherd will protect them. They may be scattered, but He will gather them up again. They shall never perish. May they backslide? Yes. Will they perish? No. The sheep may get into a pigpen, but there has never yet been a sheep in a pigpen that stayed there. Sheep and pigs do not live together. The sheep is always a sheep. No enemy, no man, no created being can pluck them out of the Savior's hand. This is wonderful!
One time a fellow gave me the argument that one can jump out of His hand because we are free moral agents. Listen to the passage. It actually says "no created thing shall pluck them out of my hand." He is the Shepherd. He is God. If you think you can jump out, the Father puts His hand right down on you, and you can't do any jumping. Brother, He's got you and you can't get loose. Both hands are the hands of Deity. No created thing can take the sheep out of His hand.
Years ago a Texas rancher told me about sheep. He said he had two thousand sheep, and someone had to be watching them all the time. If two little sheep go over the hill and get half a mile from the flock, they are lost. They cannot find their way back by themselves. The only way in the world they can be safe is for the shepherd to be there. If a wolf would come up and eat one of the little sheep, you'd think the other one would be smart enough to say, "He ate my little brother; so I'll go back over the hill and join the flock." No, he doesn't know where to go. All he does is go "Baa" and run around and wait to be dessert for the wolf. A sheep is stupid. Neither has a sheep any way to defend himself. A sheep can't even outrun his enemy. If a sheep is safe, it is not because the sheep is clever or smart. It is because he has a good shepherd.
When I say to you that He gives me eternal life and I shall never perish, you may accuse me of bragging. No, my friend, I am not bragging on myself; I'm bragging about my Shepherd. I have a wonderful Shepherd. He won't lose any of His sheep. If He starts with one hundred, He will not end with ninety-nine. If one gets lost, He will go out and find it. None will be lost.
—From Edited Messages on John by J. Vernon McGee