"God thought and thought" ..what is the sound device used?

Repetition of the word thought and the "o" sound in God.

Ms. Sue is right. It's called assonance -- repetition of vowel sounds.

http://www.answers.com/assonance

The sound device used in the phrase "God thought and thought" is called alliteration. Alliteration is a literary technique where the initial sounds of neighboring or closely connected words are repeated. In this case, the repetition of the "th" sound in "thought" creates an alliterative effect. Alliteration can be used to add rhythm, emphasis, and musicality to writing.