This refers to another disciple whose name was Judas, not to the disciple who was from the village of Kerioth who betrayed Jesus. (See: [[rc://en/ta/man/translate/translate-names]])
Here the word "show" refers to revealing how wonderful Jesus is. Alternate translation: "Why will you reveal yourself only to us" or "Why will you only let us see how wonderful you are?"
Here "world" is a metonym that represents the people who oppose God. Alternate translation: "not to those who do not belong to God" (See: [[rc://en/ta/man/translate/figs-metonymy]])