Is it farther or further?
late 14c., "mental suffering" (especially that of Christ in the Garden of Gethsemane), from Old French agonie, agoine "anguish, terror, death agony" (14c.), and directly from Late Latin agonia, from Greek agonia "a (mental) struggle for victory," originally "a struggle for victory in the games," from agon "assembly for a contest," from agein "to lead" (see act (n.)). Sense of "extreme bodily suffering" first recorded c.1600.
contest; wrestling; severe struggling with pain and suffering. Anguish is the reflection on evil that is already past, while agony is a struggle with evil at the time present. It is only used in the New Testament by Luke (22:44) to describe our Lord's fearful struggle in Gethsemane. The verb from which the noun "agony" is derived is used to denote an earnest endeavour or striving, as "Strive [agonize] to enter" (Luke 13:24); "Then would my servants fight" [agonize] (John 18:36). Comp. 1 Cor. 9:25; Col. 1:29; 4:12; 1 Tim. 6:12; 2 Tim. 4:7, where the words "striveth," "labour," "conflict," "fight," are the renderings of the same Greek verb.