When Jesus taught about sheep He outlined certain identifying markers by which we could know who they were. Sheep, Jesus taught, have a characteristic way of thinking and behaving. The purpose of His teaching was to give us a criteria for deciding which people were true and false followers. Jesus said that His sheep (1) hear His voice, (2) recognize His voice and (3) respond to His voice by following Him. Thus before a person can be considered in the flock of the Lord Jesus there has to be understanding, recognition, relationship and submission. Others forms of life might look like sheep on the outside but they lack these qualities. For instance, He warned:
15 “Beware of false prophets, who come to you in sheep’s clothing but inwardly are ravenous wolves. 16 You will recognize them by their fruits. Are grapes gathered from thornbushes, or figs from thistles? 17 So, every healthy tree bears good fruit, but the diseased tree bears bad fruit. 18 A healthy tree cannot bear bad fruit, nor can a diseased tree bear good fruit. 19 Every tree that does not bear good fruit is cut down and thrown into the fire. 20 Thus you will recognize them by their fruits (Matthew 7:15-20).
Among these unhealthy diseased trees are many religious people who think they are doing God a service but are poisoning the flock. As for wolves, a person need not necessarily preach another religion to be a wolf. Many false prophets in Israel were teaching the right doctrine. They were just misrepresenting what God was telling the people in the moment.
16 You will know them by their fruits. Are grapes gathered from thornbushes, or figs from thistles? 17 So, every healthy tree bears good fruit, but the diseased tree bears bad fruit. 18 A healthy tree cannot bear bad fruit, nor can a diseased tree bear good fruit. 19 Every tree that does not bear good fruit is cut down and thrown into the fire. 20 Thus you will recognize them by their fruits (Matthew 7:16-17)
Going by what Jesus says what might we have assumed about Saul of Tarsus prior to his Damascus Road experience? We might have called him a diseased plant because he was badly infected with Phariseeism. We might have labelled him a thornbush because anyone trying to pluck fruit from his life would be hurt by his bitterness and rage. Jesus said a person's true nature is determined by their attitudes and behaviors. Saul hated the whole idea of Jesus being the Messiah and he expressed his rage by persecuting and slaughtering His followers. Killing and eating sheep is not what sheep do. It is the work of wolves.
Saying that a person’s metaphysical status as “elect” is what makes them a “sheep” overturns Jesus’ clear and simple teaching on this subject. It is equivalent to saying that a person can be a good tree that bears nothing but diseased fruit, or that they can be a fruitful plant that bears thorns, or that there is a very special kind of sheep that is carnivorous and preys on other sheep This is, of course, nonsense. “Knowing them by their fruits” means that we will be able to observe who they are and KNOW for certain whether they are true sheep or not.
A person’s future status as a believer or unbeliever is something only God knows through divine foreknowledge Unless He imparts some of that knowledge to us through prophecy we cannot possibly know it. However, God, through His divine foreknowledge is able to call people sheep before they have actually chosen to become sheep before they have developed the character of a sheep. He is able to say He already HAS other sheep in another sheep fold even though they have not yet believed or come. They are not yet sheep in time in space but merely prophetically and we who live in time and space should never confuse reality with a prophetic reference.
Knowing what people will do is not the same as predetermining their decisions. Foreknowledge preserves humanity's power to choose but allows God to use even rebellious people in His redemptive plan. Foreknowledge preempts the philosophical illogicalities and moral atrocities associated with determinism.