Let me post this from Vine's Complete Expository Dictionary of the NT on the word RANSOM.
1. lutron (G3383), lit., "a means of loosing" (from luo, "to loose"), occurs frequently in the Sept., where it is always used to signify "equivalence." Thus it is used of the "ransom" for a life, e.g., Exo_21:30, of the redemption price of a slave, e.g., Lev_19:20, of land, Lev_25:24, of the price of a captive, Isa_45:13. In the NT it occurs in Mat_20:28 and Mar_10:45, where it is used of Christ's gift of Himself as "a ransom for many." Some interpreters have regarded the "ransom" price as being paid to Satan; others, to an impersonal power such as death, or evil, or "that ultimate necessity which has made the whole course of things what it has been." Such ideas are largely conjectural, the result of an attempt to press the details of certain Old Testament illustrations beyond the actual statements of New Testament doctrines.
That Christ gave up His life in expiatory sacrifice under God's judgment upon sin and thus provided a "ransom" whereby those who receive Him on this ground obtain deliverance from the penalty due to sin, is what Scripture teaches. What the Lord states in the two passages mentioned involves this essential character of His death. In these passages the preposition is anti, which has a vicarious significance, indicating that the "ransom" holds good for those who, accepting it as such, no longer remain in death since Christ suffered death in their stead. The change of preposition in 1Ti_2:6, where the word antilutron. a substitutionarv "ransom," is used, is significant. There the preposition is huper, "on behalf of," and the statement is made that He "gave Himself a ransom for all," indicating that the "ransom" was provisionally universal, while being of a vicarious character. Thus the three passages consistently show that while the provision was universal, for Christ died for all men, yet it is actual for those only who accept God's conditions, and who are described in the Gospel statements as "the many." The giving of His life was the giving of His entire person, and while His death under divine judgment was alone expiatory, it cannot be dissociated from the character of His life which, being sinless, gave virtue to His death and was a testimony to the fact that His death must be of a vicarious nature.
