What does Matthew 25:44 mean?
At some point in the end times (Matthew 24:3), and in some way, Jesus will separate people into two groups (Matthew 25:31–33). The first group is depicted as blessed and welcome, as those elected to come to faith in Christ (Ephesians 4:1; Matthew 24:22; Mark 13:27; Romans 11:7; Titus 1:1). This is proven by their actions, which demonstrate that they do, in fact, have an obedient love for Christ (John 14:15; 1 John 3:11). Those actions, taken on behalf of others, are effectively kindnesses done to Christ (Matthew 25:40).Christ has condemned the other group, however, banishing them to eternal fire alongside The Devil and his demons (Matthew 25:41). The people of this group failed to ever meet His needs when He was hungry, thirsty, naked, sick, and in prison.
Since these people have, in a literal sense, never had the chance to see Jesus in person before, they ask how this is possible. The other aspect of their question suggests an excuse. This is somewhat like treating a person rudely, only to find out they are an authority figure, a potential customer, or a relative, and claiming, "if I had known it was you, I would not have…" True or not, this is still a sin (James 2:1; 4:17). When it comes to Jesus, this second group likely would not have served, even had they known the implications (John 5:39–40), because they were not willing to honor Christ (John 3:36).
That inaction proves the opposite of Christian love (John 13:31–35). It demonstrates that these people are not part of God's family (1 John 4:20).