Becoming callous is not too hard to do especially while we have so many people whose regards is for themselves. Callous by definition refers to the thickening for ones skin and figurative refers to the hardening of ones feelings. In the negative sense we can be pretty cruel with others in the display of callous, but in the spiritual context we can become such when it comes to evil that Satan throws at us. James tells us to resist the devil and he shall flee from us (Ja4:7), but sometimes it is so hard to resist the devil because someone might really needs to be taken care of. The hardest thing in life is to resist evil, because it presents itself as a solution to a given situation. Adam and Eve could not resist the temptation of gaining a status in life that was not promised (gen3:4-5). There are some evil good things; sort of speak, that are tempting.
Matthew 5:38-39
38 Ye have heard that it hath been said, An eye for an eye, and a tooth for a tooth: 39 but I say unto you, That ye resist not evil: but whosoever shall smite thee on thy right cheek, turn to him the other also.
The meaning of resist says “to set one’s self against, to withstand, resist, oppose”, and the context of this verse deals with a limit. Standing fast and resisting opposition is the way to spiritual war far victories; we do not run. When the scriptures say “resist not” it means leave alone or walk away. Turning the other cheek is not a sign of weakness, but of strength saying that you can not be broken(1Jhn4:4). It is a form of resisting but not in a negative way. Paul said that if your enemy is thirsty or hungry feed him and in doing so you will place heaps of coal of fire on his head(Ro12:20), suggesting that he/she will eventually feel bad about what they have done. (Running away is a sign of cowardness, and God has not given us a spirit of fear but of sound mind (2Tim1:7). A writer said that if we were to forgive and turn the other check at all times we would turn around this country like never before.