-— but Onan was not a homosexual..
and his sin was not masturbation...
Yes. I’m aware.
So what was his sin?
It was “wasting his seed,” or failing to complete the marital act.
This is immoral for the same reason that feasting and inducing vomitting is immoral. It represents the separation of the pleasurable aspect of a natural act and its natural end, i.e., nutrition, or in the case of Onanism, masturbation, and birth control, reproduction.
Ah...
The things one can ‘find’ in the bible after illuminating the penumbra.
Therefore; ANY sexual intercourse, WHERE ONE KNOWS THAT CONCEPTION IS NOT POSSIBLE would be considered sin.
That 'seed' is SURELY wasted and spilled on the ground!
That misses the point completely. It had nothing to do with "separation o fthe pleasurable aspect of a natural act and its natural end". It was the reason that he pulled out -- he did not want to father and raise a child that would be his brother's lineage rather than his own.