Most Christians have heard of the theological branches such as soteriology (pertaining to salvation), ecclesiology (pertaining to church), eschatology (pertaining to “endtimes”) & such but I was recently reminded that perhaps the most important “ology” may be hamartilogy (pertaining to sin)

One encyclopedia defines hamartiology this way:

Hamartiology (Greek: αμαρτια, hamartia, "missing the mark," "sin," + λογια, logia, "sayings" or "discourse") is the branch of Christian theology, more specifically, systematic theology, which is the study of sin with a view to articulating a doctrine of it. (source)

Quite literally it means “Sin-ology”.  The reason it may be more important than the other ologies is that before a person can realize they need salvation, they must first realize the nature of their falleness & thus all the other ologies lose meaning unless a person first understands how & why they are in sin & even what sin is.

The Bible puts it this way:

Moreover the law entered that the offense might abound. But where sin abounded, grace abounded much more, so that as sin reigned in death, even so grace might reign through righteousness to eternal life through Jesus Christ our Lord. What shall we say then? Shall we continue in sin that grace may abound? (Rom 5:20-6:1)

So, “the Law” (such as the Ten Commandments) isn’t meant to be obeyed so that people can get out sin but so that we can be shown just how sinful we really are & so that the grace of God can be applied to those helpless to obtain righteous on their own.  So, the question is then asked, “Then why not sin even more so we can have even more grace”?

The Bible answers:

Certainly not! How shall we who died to sin live any longer in it? Or do you not know that as many of us as were baptized into Christ Jesus were baptized into His death? Therefore we were buried with Him through baptism into death, that just as Christ was raised from the dead by the glory of the Father, even so we also should walk in newness of life. (Rom 6:2-4)

The problem we face today is that on one side we have the humanists who act as if mankind is not in a state of sinfulness but is “basically good” or you have some Christians who want to downplay the sinfulness of mankind to the point that we often forget our true nature.  If we forget or whitewash our true nature we may begin to diminish the importance & preciousness of grace.

Certainly we should praise God for the mercy & grace He applies, for the sacrifice made by Christ on the behalf of His sheep, the love extended while we were yet sinners, but let us not avoid calling for the world to repent of sin.  We are not talking about people merely stopping certain actions or behaviors but rather acknowledging mankind’s very nature is one of sin – from the kindly little old lady that gossips about people to the hardened criminal locked behind bars.  Mankind is “basically sinful”. (bascially = at its base, its core)

Once we begin allowing humanists or fake-love-grace-mercy type Christians start to downplay that sinful nature, is the day all the other ologies won’t matter.  That is the day people start accepting unrepentant individuals into the Body of Christ.  That is the day immorality will be something that is not only tolerated among Christians  but perhaps even celebrated as a shared humility, as if our commonality is more that we’re fellow sinners than that we’re new creatures in Christ – see 1 Cor 5.

There are even some Christians who complain that the old message of “repent & believe” won’t work anymore.  That the threat of eternal separation from God is not enough to motivate anyone to repent & believe – instead they tell us to just accept people without repentance.  Get to know them, share in their sinful nature (not necessarily their actions). Just "love" them into the Kingdom.

Indeed, where sin abounds, grace will abound.  Where sin is ignored even as sin, not only will there only be fake-grace, perhaps some people will claim grace is now covering all without the need to repent. In effect, true grace is never applied.

Sin is important because it is the darkness that allows us to see just how bright the Light of salvation really is.