Where, or what does the term/phrase "Ruthless" come from.

Is a biblical thing? I was driving to work and couldn't get it off of my mind.
The meaning of ruthless, according to the Oxford English Dictionary, is: Feeling or showing no pity or compassion; pitiless, unsparing, merciless, remorseless [1]. The etymology of ruthless is simply "ruth n. + -less suffix" [1]. So, we turn to ruth: The quality of being compassionate; the feeling of sorrow for another; compassion, pity [1,2]. Also with for [1]. Its etymology is: rue v. + -th suffix, perhaps after early Scandinavian (compare Old Icelandic hryggð) [1]. Ruthless can be defined as "without ruth" or "having no ruth" [3]. So what, then, is ruth? The noun ruth, which is now considerably less common than ruthless, means "compassion for the misery of another," "sorrow for one's own faults," or "remorse" [3]. And, just as it is possible for one to be without ruth, it is also possible to be full of ruth [3].
The word "ruthless" is derived from the old Middle English word "ruthe," which means "to rue," or "to feel regret, remorse, or sorrow." [3]  Thus, "ruthless" essentially means "without mercy" or "having no mercy." [1, 3]