Allah says;
فَمَنْ أَظْلَمُ مِمَّنِ افْتَرَى عَلَى اللّهِ كَذِبًا أَوْ كَذَّبَ بِأيَاتِهِ إِنَّهُ لَا يُفْلِحُ الْمُجْرِمُونَ
So who does more wrong than he who forges a lie against Allah or denies His Ayat! Surely, the criminals will never be successful!
Allah says that no one is more wrong, unjust and arrogant than he who invented a lie against Allah, forged claims about Allah, or claimed that Allah has sent a message to him but his claim was not true.
No one is more of a criminal or has committed greater wrong than such a person. Liars cannot be confused with Prophets. Anyone who claims such a thing, whether lying or telling the truth, will necessarily be supported by Allah with proofs and signs of his falsehood or truthfulness. The difference between Muhammad and Musaylamah the liar, was clearer to those who met both of them than the difference between forenoon and midnight when it is extremely dark. Those who are clear-sighted can distinguish via signs and proofs between the truthfulness of Muhammad and the falsehood of Musaylamah the liar!
Sajah and Al-Aswad Al-`Ansi. Abdullah bin Salam said;
"When Allah's Messenger arrived at Al-Madinah, people were scared away and I was one of them. But when I saw him, I realized that his face could never be the face of a liar.
The first thing I heard from him was his statement;
يَا أَيُّهَا النَّاسُ أَفْشُوا السَّلَامَ وَأَطْعِمُوا الطَّعَامَ وَصِلُوا الاْاَرْحَامَ وَصَلُّوا بِاللَّيْلِ وَالنَّاسُ نِيَامُ تَدْخُلُوا الْجَنَّةَ بِسَلَام
O people, spread the greetings of peace, feed others, be dutiful to your relatives and offer prayers in the night when others are asleep so that you will enter Paradise in peace."
When Dimam bin Tha`labah came to Allah's Messenger and asked him in the presence of his people -- Banu Sa`d bin Bakr;
"Who raised this heaven?"
He replied, (Allah).
He asked;"And who erected these mountains?"
He replied, (Allah).
He asked;"Who spread out this earth?"
He replied, (Allah).
Then he asked;"I ask you in the name of the One, Who raised the heavens, erected the mountains, and spread out this earth, has Allah sent you as a Messenger to all mankind"
He said,
اَللَّهُمَّ نَعَم
(By Allah, Yes)!
Then Dimam asked him about Salah, Zakah, Hajj and fasting. With every question he swore by Allah and with every response the Prophet swore also.
Dimam then said;"You indeed are telling the truth. By the One Who sent you with the truth I will not increase or decrease from what you have told me."
This man was content with the few responses of the Prophet. He was convinced of the Prophet's truthfulness by the signs that he saw and witnessed.
It was narrated that;
Amr bin Al-`As went to Musaylamah. Amr was not a Muslim at that time and he was a friend of Musaylamah. Musaylamah said;"Woe unto you `Amr. What was revealed unto your friend -- meaning Allah's Messenger -- during this period"
Amr replied;"I heard his companions reading a short but great Surah."
He asked, "And what was that"
He recited;
وَالْعَصْرِ
إِنَّ الاِنسَـنَ لَفِى خُسْرٍ
By Al-`Asr (the time). Verily, man is in loss. (103;1-2) until the end of the Surah.
Musaylamah thought for a while and then said;"Something similar to that was also revealed to me."
Amr asked;"And what is it?"
He then recited;"O Wabr, O Wabr! You are only two ears and a breast. The rest of you is hollow.' What do you think, Amr?"
Amr then said;"By Allah, you know that I know that you are a liar."
This was a statement made by an idolator in judgment of Musaylamah. He knew Muhammad and his truthfulness. He also knew Musaylamah and his tendency toward falsehood and lying. People who think and have insight know even better.
Allah said;
وَمَنْ أَظْلَمُ مِمَّنِ افْتَرَى عَلَى اللَّهِ كَذِباً أَوْ قَالَ أُوْحِى إِلَىَّ وَلَمْ يُوحَ إِلَيْهِ شَىْءٌ وَمَن قَالَ سَأُنزِلُ مِثْلَ مَأ أَنَزلَ اللَّهُ
And who does more aggression and wrong than he who invents a lie against Allah or rejects His Ayat. (6;21)
فَمَنْ أَظْلَمُ مِمَّنِ افْتَرَى عَلَى اللّهِ كَذِبًا أَوْ كَذَّبَ بِأيَاتِهِ إِنَّهُ لَا يُفْلِحُ الْمُجْرِمُونَ
So who does more wrong than he who forges a lie against Allah or denies His Ayat Surely, the criminals will never be successful!
No one is more unjust than he who belies the truth which the Messengers have brought supported with evidence and proof