(Say: "O mankind! I am (sent) to you only as a plain warner.'') meaning, `Allah has sent me to you to warn you ahead of the terrible punishment, but I have nothing to do with your reckoning. Your case rests with Allah: if He wills, He will hasten on the punishment for you; and if He wills, He will delay it for you. If He wills he will accept the repentance of those who repent to Him; and if He wills, He will send astray those who are decreed to be doomed. He is the One Who does whatsoever He wills and wants and chooses.
(I am (sent) to you only as a plain warner. So those who believe and do righteous good deeds,) means, whose hearts believe and whose actions confirm their faith.
لَّهُم مَّغْفِرَةٌ وَرِزْقٌ كَرِيمٌ
(for them is forgiveness and Rizq Karim. ) means, forgiveness for their previous bad deeds, and a great reward in return for a few good deeds. Muhammad bin Ka`b Al-Qurazi said, "When you hear Allah's saying:
(Rizq Karim) this means Paradise.''
وَالَّذِينَ سَعَوْاْ فِى ءَايَـتِنَا مُعَـجِزِينَ
(But those who strive against Our Ayat to frustrate them,) Mujahid said, "To discourage people from following the Prophet.'' This was also the view of `Abdullah bin Az-Zubayr, "to discourage.'' Ibn `Abbas said, "To frustrate them means to resist the believers stubbornly.''
أُوْلَـئِكَ أَصْحَـبُ الْجَحِيمِ
(they will be dwellers of the Hellfire.) This refers to the agonizingly hot Fire with its severe punish- ment, may Allah save us from it. Allah says:
(Those who disbelieved and hinder (men) from the path of Allah, for them We will add torment to the torment because they used to spread corruption) 16:88
Maududi - Sayyid Abul Ala Maududi - Tafhim al-Qur'an
That is, "I am merely a warner and not the maker of your destinies. It is Allah Who passes judgment and decides about the punishment."
"The Believers shall have forgiveness" means that Allah will overlook their faults, weaknesses, and acts of omission and commission. They will have "honorable provisions" means that they will have excellent supplies which will be given to them in an honorable way.