What does the Bible say about the marks of Christ's sheep?

According to Matthew 25:31-46, the five marks of Christ's sheep are: first, they are blessed by the Father, who calls them 'blessed' and prepares a kingdom for them from the foundation of the world. Second, they are heirs, inheriting a kingdom prepared by God. Thirdly, they are righteous; despite their sense of unworthiness, they are called righteous because they have faith in Christ. Fourth, they serve Jesus Christ by serving others. Finally, they confess their sins, recognizing their need for Christ's righteousness. These marks help us discern true believers from those who merely appear religious.