'Natural' in the Bible

For this reason God gave them over to degrading passions; for their women exchanged the natural function for that which is unnatural,

and in the same way also the men abandoned the natural function of the woman and burned in their desire toward one another, men with men committing indecent acts and receiving in their own persons the due penalty of their error.

for if God did not spare the natural branches, He will not spare you, either.

For if you were cut off from what is by nature a wild olive tree, and were grafted contrary to nature into a cultivated olive tree, how much more will these who are the natural branches be grafted into their own olive tree?