"to put to death" (from thanatos, "death," akin to thnetos, "mortal," see above), is translated "mortify" in Romans 8:13 (Amer. RV, "put to death"); in Romans 7:4 , "ye were made dead" (Passive Voice), betokens the act of God on the believer, through the death of Christ; here in Romans 8:13 it is the act of the believer himself, as being responsible to answer to God's act, and to put to death "the deeds of the body." See DEATH , C, No. 1.

2: νεκρόω

(Strong's #3499 — Verb — nekroo — nek-ro'-o )

"to make dead" (from nekros, see DEAD , A), is used figuratively in Colossians 3:5 and translated "mortify" (Amer. RV, "put to death"). See DEAD , B, No. 1.

Bibliography Information
Vines, W. E., M. A. Entry for 'Mortify'. Vine's Expository Dictionary of NT Words. https://www.studylight.org/dictionaries/eng/ved/m/mortify.html. 1940.

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Vine's Expository Dictionary of NT Words

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Mortify