For this reason God allowed [or, abandoned] them to [practice] degrading passions; for their women exchanged the natural function [i.e., of sex] for what is against nature [i.e., lesbianism].

And men did the same thing, leaving the natural function [i.e., of sex] with women, and burning in their desire for each other. Men committed indecent [sexual] acts with other men [i.e., homosexuality], and [so] brought on themselves the penalty they deserved for this perversion.

they do not have any sense; they do not keep their promises; they fail to show natural affection; and they are merciless.

For we know that the law of Moses is spiritual [i.e., from the Holy Spirit in origin and character], but I am fleshly, sold as a slave to sin. [Note: "Flesh" throughout this section refers to a person's natural inclinations to sin].

Therefore, you should not brag [about your superiority] over the [natural] branches [i.e., the rejected Jews]. But, if you must brag, it should not be over you [Gentiles] nourishing the roots [i.e., the Jews], but over the roots nourishing you.

For if God did not spare the natural branches [i.e., the Jews], He will not spare you [Gentiles] either.

For you [Gentiles] were cut off from a natural wild olive tree and [then], contrary to the natural process, were grafted into a cultivated olive tree. [Since that has happened], how much more likely is it for these [Jews], who are the natural branches, to be grafted [back] into their own olive tree [again]?

Now the natural person [Note: Since this person is contrasted with the spiritual person of verse 15, it is taken here to mean the person without the Holy Spirit] does not receive the things [i.e., truths] revealed by the Holy Spirit of God, because they are [considered] foolishness to him. And he cannot understand them because they must be discerned by using spiritual judgment [i.e., judgment aided by the Holy Spirit].

Although we are Jews by natural birth, and not sinful Gentiles [who do not have a relationship with God],

Now the son [Ishmael], born to the slave woman, was born simply of their natural relationship; but the son [Isaac], born to the free woman, was born in fulfillment of a [divine] promise.

All of us [Jews] also once lived among such people, fulfilling the improper cravings of our physical being and doing what our bodies and minds desired. In this natural [unconverted] state we were deserving of [God's] wrath, just like the rest [of mankind].

lacking in natural affection, unwilling to be reconciled [to their enemies], slanderers, lacking self-control, brutal, haters of what is good,

For if anyone is [only] a listener to the word and does not practice it, he is like a person who sees his natural face in a mirror,

These are people who cause divisions [among God's people]; they follow their natural inclinations [i.e., worldly principles], for they do not have the Holy Spirit [in their lives].