I've never gotten a clear answer on this issue. Worse, I don't know if I've ever even seen two Christians agree on this.
Well there's a first for everything, cause I agree with
@Everybodyknows heh
Worst, this is the criteria by which we will be evaluated as worthy of eternal hellfire, and yet we have no access to this criteria.
The evaluation for hellfire is not a moral test so we don't need to have access to some kind of ruleset or moral list. With regard to eternal life the Bible talks of two groups, one group receives spiritual connection with the Spirit of God through Jesus and enters into eternal life in heaven. The other group rejects spiritual connection and enters into eternal death in hell. "Spiritual connection" is available to every person who has ever lived unconditionally. Jesus came to bring forgiveness to everyone, not to bring a list of rules and then judge people according the rules. Jesus came to forgive and restore mankind relationship with God in a spiritual sense--hence why I am using the term "spiritual connection". Paul wrote in Ephesians 2:8-9:
For it is by grace you have been saved through faith, and this not from yourselves; it is the gift of God, not by works, so that no one can boast.
The purpose of this thread is for someone to present a clear definition of sin. I must be able to apply your definition to any conceivable scenario and determine for myself if an action qualifies as sinful.
Morality for Israel was loosely defined by the Old Testament Law. However it is not an objective morality that remains for all people of all times. It was an objective morality for the people of Israel because they accepted to obey those external laws. Jesus then summed up the heart of the law with, love God with all your heart and love your neighbour as yourself. But then Jesus gave a new law in John 13:34,
A new command I give you: Love one another. As I have loved you, so you must love one another.
So the beginning point of all morality is
love. And we know what love looks like: it is self-sacrificing, it is healing, it stands up for what is right, because we find these and many more things in the life of Jesus. Paul also writes about what love looks like in the classic wedding passage of 1 Corinthians 13 verses 4 to 7 specifically:
Love suffers long and is kind; love does not envy; love does not parade itself, is not puffed up; does not behave rudely, does not seek its own, is not provoked, thinks no evil; does not rejoice in iniquity, but rejoices in the truth; bears all things, believes all things, hopes all things, endures all things.
But how do we describe so broad a concept as love? How do we narrow it down to a list of rules or guidelines? The christian life is to be transformed into love, for every decision and every motive to be fundamentally based on love. Then, when practical decisions need making, if we are unsure, we pray, we discuss, we wait 'till we feel peace, we work together towards love. We are not relying on a list of guidelines but on the Law of Love written on our hearts, our minds, the life of Jesus, how a child would think etc.
Not every decision is either loving or sinful. If I choose to type the word awesome instead of the word excellent it doesn't really matter either way. It is neutral. But if a decision is moral, then there are loving and sinful options. Interestingly, what one might consider to be loving, another might consider sinful. Continued discussion, prayer etc is needed. It is similar to how democracy deals with morality.
Thus to be clear, I do not believe christianity offers a clear objective morality, but a subjective morality relying on group consensus through prayer and discussion based on love. I also realise this leaves open the door for some potentially strange ideas, hence the need for group consensus and always falling back on the life of Jesus and the most basic understanding of love as presented in the Bible.