(18:2) [He has made it] straight, to warn of severe punishment from Him and to give good tidings to the believers who do righteous deeds that they will have a good reward
Muhammad Taqi-ud-Din al-Hilali and Muhammad Muhsin Khan,
(18:2) (He has made it) Straight to give warning (to the disbelievers) of a severe punishment from Him, and to give glad tidings to the believers (in the Oneness of Allah Islamic Monotheism), who work righteous deeds, that they shall have a fair reward (i.e. Paradise).
Mohammed Marmaduke William Pickthall
(18:2) (But hath made it) straight, to give warning of stern punishment from Him, and to bring unto the believers who do good works the news that theirs will be a fair reward,
Abdullah Yusuf Ali
(18:2) (He hath made it) Straight (and Clear) in order that He may warn (the godless) of a terrible Punishment from Him, and that He may give Glad Tidings to the Believers who work righteous deeds, that they shall have a goodly Reward,
Mohammad Habib Shakir
(18:2) Rightly directing, that he might give warning of severe punishment from Him and give good news to the believers who do good that they shall have a goodly reward,
Dr. Ghali
(18:2) Most upright, to warn of strict violence from very close to Him, and to give good tidings to the believers who do very deeds of righteousness that they will have a fair reward,
Ali Unal
(18:2) (He has made it) unerringly straight, to warn of a stern punishment from Him and give the believers who do good, righteous deeds the glad tidings that for them is an excellent reward (Paradise),
Amatul Rahman Omar
(18:2) (He has made it) rightly directing, that it may warn (the disbelievers) of a severe calamity (coming) from Him and that it may give good tidings to the believers who do deeds of righteousness, that there awaits them a (place of) goodly reward,
Literal
(18:2) A straight/valuable (Book) to warn/give notice (of) a severe power/might from at Him, and (it) announces good news (to) the believers those who make/do the correct/righteous deeds , that (E) for them (is a) good/beautiful reward .
Ahmed Ali
(18:2) Immutable, so that it may warn of a severe punishment from Him; and give happy tidings to those who believe and do the right that there is a better reward (of Paradise) for them,
A. J. Arberry
(18:2) right, to warn of great violence from Him, and to give good tidings unto the believers, who do righteous deeds, that theirs shall be a goodly wage
Abdul Majid Daryabadi
(18:2) Straightforward, that it may warn of a severe violence from before Him, and bring glad tidings to the believers who work righteous works that theirs shall be a goodly hire.
Maulana Mohammad Ali
(18:2)-
Muhammad Sarwar
(18:2) so that he could warn them of His stern retribution, give the glad news of the best and everlasting reward to the righteously striving believers,
Hamid Abdul Aziz
(18:2) (He made it) Straight, to give warning of stern punishment from Him; and to give the glad tidings to the believers, who do what is right, that for them is a goodly reward,
Faridul Haque
(18:2) A just Book, to warn of Allahs severe punishment, and to give glad tidings to the believers who do good deeds, that for them is an excellent reward.
Talal Itani
(18:2) Valuableto warn of severe punishment from Himself; and to deliver good news to the believers who do righteous deeds, that they will have an excellent reward.
Ahmed Raza Khan
(18:2) A just Book, to warn of Allahs severe punishment, and to give glad tidings to the believers who do good deeds, that for them is an excellent reward.
Wahiduddin Khan
(18:2) and which rightly directs, to give warning of stern punishment from Him, and to proclaim to the believers who do righteous deeds that they shall have an excellent recompense,
Safi-ur-Rahman al-Mubarakpuri
(18:2) (He has made it) straight to give warning of a severe punishment from Him, and to give good news to the believers, who do righteous deeds, that they shall have a fair reward.
Ali Quli Qarai
(18:2) [a Book] upright, to warn of a severe punishment from Him, and to give good news to the faithful who do righteous deeds, that there shall be for them a good reward,
Hasan al-Fatih Qaribullah and Ahmad Darwish
(18:2) unswerving. To warn of great violence from Him, and to give good tidings to the believers who do good deeds that theirs shall be a goodly wage
That is translated surah Al kahf ayat 2 (QS 18: 2) in arabic and english text, may be useful.