John 13:35 By this shall all [men] know that ye are my disciples,

Greek : 

Literal Verse: 

In this, all will see you as my students, if you hold to your mutual affection.

KJV : 

By this shall all [men] know that ye are my disciples, if ye have love one to another.

Interesting and Hidden Aspects: 

Loving one another may not seem like a challenge, but Christ seems to have seen it as difficult because he saw being his disciple as a challenge.

The Greek word for "disciple" (mathetes) is used constantly in the gospels, but seldom in the words of Christ. He doesn't use it at all until he describes the difficulty of being his disciple in Luke (Luke 14:26, Luke 14:27, Luke 14:27). He uses the word again in John (Jhn 8:31, then here, and again in John 15:8). That is all he has to say on the subject.

In all of these statements, Jesus recognizes the difficulties of being his student. These challenges are different and more difficult than simply believing in him, which is all he asks.

Related Verses: 

Greek Vocabulary: 

τούτῳ "This" is toutô (touto), which means "from here", "from there", "this [thing]," or "that [thing]."

πάντες "All [men]" is from pas (pas), which means "all", "the whole", "every", "anyone", "all kinds," and "anything."

γνώσονται "know," is from gignôskô (ginosko) which means "to learn to know", "to know by reflection or observation," and "to perceive."

μαθηταί "Disciples" is from mathêtês (mathetes), which means "learner", "pupil", "apprentice," and "student."

ἐάν "If" is from ean, which is a conditional particle (derived from ei (if) and an (might)) which makes reference to a time and experience in the future that introduces but does not determine an event.

ἀγάπην "Love" is from agape, which means "the love of a husband and wife", "love of God by man", "brotherly love", "charity," and "alms."

"Ye have" is from echô (echo), which means "to have", "to hold", "to possess", "to keep", "to have charge of", "to maintain", "to hold fast", "to bear", "to keep close", "to keep safe," and "to have means to do."

ἀλλήλους "One with another" is from allêlôn (allelon), which means "one another", "to one another", "mutually," and "reciprocally."