Why is shirk such a big sin?

Answer 1

Shirk is the greatest major sin because it involves associating others along with Allah in worship, His Lordship or in His attributes. Being thankful to other than Allah for all the good which He has given us, or to say that He has an equal or one who is similar to Him, shirk can also involve rejecting the Messengers' of Allah since the Messengers of Allah call against shirk.

If someone rejects any Messenger of Allah, they are rejecting His message. If they are rejecting His Message, they are saying that Allah has lied and that He doesn't send us a Criterion to judge between what is right and wrong, true and false etc. If someone doesn't accept this, then they are following a way which opposes the law of Allah. They are also saying that Allah has lied, and that in of itself is a huge sin.

So because they have rejected Allah's message, they have also rejected His commandments. Which then means that they would be disobedient to Him without even feeling any guilt that they are transgressing the boundaries which He has set for us. This means that they can do any forms of injustice without feeling that they will return to Allah and be judged for what they did (and be either rewarded or punished for their actions), so they may persist in these evils to the extent that they cause a great deal of harm to the whole of humanity.

Yet if this person never had commited this shirk, and they had accepted Allah's Messengers', this would mean they would accept His call, which would mean that they would be far more likely to do good and turn away from evil because they would have the fear of Allah, love of Allah, hope for His reward for their patience and good etc.

So maybe if this person never had fallen into shirk, they may have done alot less evil out of fear of Allah, and the world would be a better place for the person aswell as those affected by this person.