The general concept of sin in Islam
So far we have concentrated on the sin of disbelief in Islam. To wrap up that discussion it is necessary to put it into context within the general concept of sin in Islam. A sin is an act in contrast to the will of Allah. We can act following His will, this is the meaning of the word Islam, or we can fail to pay attention to His will or we can deliberately act against His will. Islam is submission to the will of Allah. The purpose of our existence as Human beings is to worship and serve Allah - to do His will.
This is made clear in the Qur'an:
"I have only created Jinns and men, that they may serve Me."
Surah 51 Verse 56
Yusuf Ali Translation:
"I created the jinn and humankind only that they might worship Me." Pickthall Translation:
The most important names of Allah are ones expressing His compassion towards creation - Ar-Rahmaan and Ar-Raheem. These mean the most full of compassion and mercy (Ar-Rahmaan) and the most giving in that compassion and mercy (Ar-Raheem). The foundation of worship / service to Allah is to become humbly grateful for the great gifts we already have from Allah and as a result to seek to please Allah through serving Him. This happens through gaining knowledge of creation and recognition of the revelation sent by Allah to Mankind and learning to value and appreciate it. We then serve Allah by building in and on that creation to add ever more real value to it.
To serve Allah our intentions must reflect His intentions; our wills must be consciously submitted to His will. The basic principle for us then is to reflect Allah's 'rahma' by showing compassion and mercy towards Allah's creation in the hope, and with the assurance, that Allah will show compassion and mercy towards us.
One of Allah's greatest gifts is the gift of moral guidance through revelation. If we follow it, it brings the greatest benefits in this life and the next. It is in trying to do this that our intentions are purified and it is by our intentions that we are judged.
A fundamental precept of Islam is that Human nature is essentially good. There are many elements to Human nature and each one has the potential to bring benefits.
In general we can say that a sin is committed when someone causes harm to themselves or to others or to any part of creation. The guilt depends on the intention of the sinner. In its most extreme form someone does deliberately harmful and destructive acts rejecting any appeals to do what is for their own benefit never mind what is beneficial for others. They may claim that it makes no difference anyway since existence is pointless and therefore have no gratitude for the benefits they have in life.
The contrast to this is someone who tries to improve himself, others and all of creation. They believe in God and are always grateful to Him for all they have in life. Their works to improve creation flow from their will to please God.
Human beings have the capacity to sin largely as a result of having the capacity to plan. When someone plans their efforts, they need to be able to suppress their natural desires for a time. This is quite different from animals that live from moment to moment obeying their perceptions of the present and their instinctive drives. This is indeed a dramatic difference. Human beings are able to look to the future - conceptualise it and form an intention to act. This conscious intention can override even the most powerful of our instincts. Through it we have capacity to cause ourselves harm in the short term in order to realise the greater good in the long term. As an inevitable part of this we gain the potential to cause ourselves harm, i.e. the potential to sin.
We cannot see clearly into the future. What we do instead is to believe in some future circumstances and direct our actions accordingly. Taking planning to its logical limits we would try to do what is for the good over all time and certainly for our entire life (in this world and the next). This is the core of trying to do what is morally right. It is trying to do what is for the ultimate good. It is trying to do what Allah wills.