'Theo' is the Greek word for God and 'logy' means 'word' or 'study', hence theology is the study of God's word. Jesus said, My teaching is not my own. It comes from him who sent me. If anyone chooses to do God's will, he will find out whether my teaching comes from God ...
(John 7:16)
The Katha Upanishad is an ancient scripture from India. If you want to know its meaning, read more...