The Scofield Bible Commentary, by Cyrus Ingerson Scofield, [1917], at sacred-texts.com
sister
A wife who is a sister.
carnel
That is, things for the body.
without
The expression is peculiar and might be literally rendered, "not lawless toward God, but inlawed to Christ."
See "Law (of Christ)," (Gal 6:2); (Jo2 1:5).
It is another way of saying, "not under the law, but under the rule of grace." (Rom 6:14).
save
(See Scofield) - (Rom 1:16).
race
Race-course.
castaway
(Greek, "adokimos", "disapproved"). Greek, "dokimos", without the private, "a", is translated "approved" in (Rom 14:18); (Rom 16:10); (Co1 11:19); (Co2 10:18); (Co2 13:7); (Ti2 2:15); and in (Jam 1:12); by the word "tried." The prefix simply changes the word to a negative, that is, not approved, or, disapproved. The apostle is writing of service, not of salvation. He is not expressing fear that he may fail of salvation but of his crown.
See "Rewards"; (Dan 12:3); (Co1 3:14).