The words obedience, obedients sound the same but have different meanings and spellings. Why do obedience, obedients sound the same even though they are completely different words?
The answer is simple: obedience, obedients are homophones of the English language.
The quality or condition of being obedient.
The act of obeying.
A sphere of ecclesiastical authority.
A group of people under such authority.
Definitions from The American Heritage® Dictionary of the English Language, 4th Edition, and Wordnik.
Homophones (literally "same sound") are usually defined as words that share the same pronunciation, regardless of how they are spelled.
If they are spelled the same then they are also homographs (and homonyms); if they are spelled differently then they are also heterographs (literally "different writing").