The first hurdle to accept here is that, though the parable appears to apply directly to that time after Christ's return when He is ruling the nations, the instruction also applies in principle to us. In other words, His children can never ignore this instruction. What sets this parable apart is that Jesus specifically focuses on works regarding our relationships with and services to our brethren.
Clearly, failure in this indicates sin. We need to grasp two major principles involved in sin: First, sin describes failure, the failure to live up to or meet God's standard. Second, sins can be acts of commission and/or omission. Sin is a direct act of evil against another or a failure to do something good, in this case, something God would expect.
How important are works even though they do not save us? Revelation 20:12-13 reveals that those who commit the unpardonable sin earn for themselves the punishment of being cast into the Lake of Fire. That is their “reward” for their evil works or no works.
On the other hand, Jesus declares in Matthew 16:25, 27:
For whoever desires to save his life will lose it, but whoever loses his life for My sake will find it. . . . For the Son of Man will come in the glory of His Father with His angels, and then He will reward each according to His works.
John W. Ritenbaugh
Ecclesiastes and Christian Living (Part Two): Works
Understanding the Parable of the Sheep and the Goats lies in their surprised responses. Both the sheep and the goats respond, "When did we see you in need and help you?" (verses 37-39, 44). This parable contains two lessons.
The first lesson is that neither the sheep nor the goats are surprised at the place Christ assigns them. A careful reading of the parable shows that clearly. They do not respond to the place that Christ assigns them, but they express surprise at the reasons He gives for His judgment. A vital question to Christians is, on what does He base his judgment? The basis of His judgment is how they treated Christ! Of course, their treatment of Christ manifests itself in how they treated those in whom Christ lived, those who had His Spirit.
The second lesson is no less important than the first. Jesus, our Judge, eliminates the possibility of hypocrisy obscuring His judgment of the sheep and the goats. If the goats had thought that treating their brothers in the faith would have gotten them into the Kingdom, they would have done it. What is the lesson? Jesus is interested in love from the heart, not a false love.
The true love of God is seen in the sheep. As the sheep respond to their brother's need, they are united in their distress and at the same time unwittingly, unconsciously, without hypocrisy, align themselves with Christ. Apparently, they are not even aware of what they were doing. This is a kind of love that cannot be faked or put on. "By this all will know that you are My disciples, if you have love for one another" (John 13:35).
The reaction of the goats is quite different. They have little sympathy for God's way and remain indifferent, Laodicean, to their brethren. In so doing, they reject their Messiah, their King, since He lived in the people whom they would not serve. The goats are condemned because of their sins of omission.
Because they had developed their relationship with Christ through prayer, Bible study, fasting, and obedience, the sheep have love through a regular infusion of the Spirit of God. "[T]he love of God has been poured out in our hearts by the Holy Spirit who was given to us" (Romans 5:5). A godly life always comes down to the basic things. The sheep are simply unconsciously and unaffectedly good, kind, sympathetic, and concerned, attributes of character that cannot be feigned.
John W. Ritenbaugh
The World, the Church, and Laodiceanism
Other Forerunner Commentary entries containing Matthew 25:31:
2 Thessalonians 1:7-10