how did slavery cause the civil war

Choose one of the following historical figures (Abraham lincoln/ frederick douglass) and assume the perspective of the person as you write the diary entry or letter.  Your goal is to share your thoughts about how conflict over slavery caused the Civil War.
Your response should include: 

A thesis/claim that states how slavery caused the war
Provide context by summarizing what was going on during this time and how slavery caused the Civil War.
Evidence from at least two (2) documents that support your thesis/claim

Do not forget to cite your evidence/sources

Your hopes and/or fears about the Civil War that are consistent with the perspective of the historical figure you are writing about (Either Douglass or Lincoln)