You wrote, "But you shouldn't need a single verse to say one thing for that one thing to be true."
There is a principle in scripture that establishes truth in the mouth of two or three witnesses. Jesus even applies it to himself.
John 5:31
If I alone bear witness about myself, my testimony is not true.
When considering hermanuetics it is s not a bad plumb line, especially in light of how easily a single verse can be misunderstood.