Allah commands His believing servants to remain steadfast in their obedience and have Taqwa of Him.
(Say: "O My servants who believe, have Taqwa of your Lord. Good is for those who do good in this world...") means, the one who does good deeds in this world, will have a good (reward) in this world and in the Hereafter.
(and Allah's earth is spacious!) Mujahid said, "So emigrate through it and strive hard and keep away from idols."
(Only those who are patient shall receive their reward in full, without reckoning.) Al-`Awza`i said, "Their reward will not be weighed or measured; they will be given an immense reward." As-Suddi said:
(Only those who are patient shall receive their reward in full, without reckoning.) means, "In Paradise."
(Say: "Verily, I am commanded to worship Allah, making religion sincerely for Him...") means, `I am commanded to worship Allah alone in all sincerity, with no partner or associate.'
(And I am commanded (this) in order that I may be the first of the Muslims.)