# Oh, if only I had someone to hear me!

"I wish I had someone to hear me" or "I wish that someone would listen to me"

# here is my signature

"I solemnly promise that all I have said is true"

# let the Almighty answer me!

"let the Almighty tell me what I have done wrong". An answer probably refers to telling Job what wrong he accuses Job of doing.

# If only I had the indictment that my opponent has written!

"If only I could read my opponent's complaint against me"

# my opponent

These words could refer to God or someone else.