Quran Surat An-Nisa (Women) 4-Verse:86 (When ye are greeted with a greeting (Salam Aliakum), greet ye with a better than it or return it. Lo! Allah taketh count of all things.)

Quran V4:86

وَإِذَا حُيِّيتُم بِتَحِيَّةٍ فَحَيُّوا بِأَحْسَنَ مِنْهَا أَوْ رُدُّوهَا ۗ إِنَّ اللَّهَ كَانَ عَلَىٰ كُلِّ شَيْءٍ حَسِيبًا[86]

{ وإذا حُيِّيتم بتحية } كأن قيل لكم سلام عليكم { فحيُّوا } المحيِّي { بأحسن منها } بأن تقولوا له عليك السلام ورحمة الله وبركاته { أوردُّوها } بأن تقولوا له كما قال أي الواجب أحدهما والأول أفضل { إن الله كان على كل شيء حسيبا } محاسبا فيجازي عليه ومنه ردُّ السلام وخصّت السنة الكافر والمبتدع والفاسق والمسلِّم على قاضي الحاجة ومن في الحمام والآكل فلا يجب الرد عليهم بل يكره في غير الأخير ويقال للكافر وعليك .

{And when you are greeted with a greeting} such as when it is said to you, “ Salam Alaikum - Peace be upon you,” {then greet the one who greets you with a better one} by saying to him, “Peace be upon you and the mercy of Allah and His blessings,” {or return it} by saying to him as he said, meaning one of them is obligatory, and the first is better. {Indeed, Allah is ever, over all things, an Accountant} an Accountant, so He will reward for it, and from it is the return of the greeting. 

The Sunnah has specified the disbeliever, the innovator, the sinner, the one who greets the one relieving himself, the one in the bathhouse, and the one eating, so it is not obligatory to return to them, rather it is disliked in other than the last, and it is said to the disbeliever, “And upon you.”

English  Quran V4:86

When you are greeted with a greeting, greet in return with what is better than it, or (at least) return it equally. Certainly, Allah is Ever a Careful Account Taker of all things.

French

Si on vous fait une salutation, saluez d'une façon meilleure; ou bien rendez-la (simplement) . Certes, Allah tient compte de tout.

German

Und wenn euch ein Gruß entboten wird, dann grüßt mit einem schöneren (zurück) oder erwidert ihn. Gewiß, Allah ist über alles ein Abrechner.

Portuguese

Quando fordes saudados cortesmente, respondei com cortesia maior ou, pelo menos, igual, porque Deus leva em contatodas as circunstâncias.

Spanish

Si os saludan, saludad con un saludo aún mejor, o devolvedlo igual. Alá tiene todo en cuenta.

Swedish

När någon riktar en hälsning till er, besvara den då med en hövligare hälsning eller med samma ord. Gud håller räkning på allt.

Russian 

Когда вас приветствуют, отвечайте еще лучшим приветствием или тем же самым. Воистину, Аллах подсчитывает всякую вещь.

Bangla

আর তোমাদেরকে যদি কেউ দোয়া করে, তাহলে তোমরাও তার জন্য দোয়া কর; তারচেয়ে উত্তম দোয়া অথবা তারই মত ফিরিয়ে বল। নিশ্চয়ই আল্লাহ সর্ব বিষয়ে হিসাব-নিকাশ গ্রহণকারী।

 Odia Quran V4:86

ଓଡ଼ିଆ କୋରାନ୍ ଶ୍ଲୋକ ୪:୮୬

ଏବଂ ଯେତେବେଳେ ତୁମକୁ ଶାନ୍ତି ପାଇଁ ପ୍ରାର୍ଥନା କରାଯାଏ, ତେବେ ଶାନ୍ତି ପାଇଁ ଏକ ଉତ୍ତମ ପ୍ରାର୍ଥନା କର କିମ୍ବା ତାହାକୁ ଫେରାଇ ଦିଅ। ନିଶ୍ଚିତ ଭାବରେ, ଆଲ୍ଲାହ ସବୁକିଛି ପାଇଁ ଦାୟୀ।

odia koran sloka cha:atirisi  (Translated from Hindi )

abng jetebele tumaku santi pain praarthana karajae, tebe santi pain eka uttama praarthana kara kimba tahaku ferai dia. nischita bhabare, allaaha sabukichhi pain dayi.

Hindi  Quran V4:86

और तुम्हें जब सलामती की कोई दुआ दी जाए, तो तुम सलामती की उससे अच्छी दुआ दो या उसी को लौटा दो। निश्चय ही, अल्लाह हर चीज़ का हिसाब रखता है|

Chinese Quran V4:86

有人以祝詞祝賀你們的時候，你們當以更好的祝詞祝賀他，或以同樣的祝詞回答他，真主確是監察萬物的。

Japanese

あなたがたが挨拶された時は，更に丁重な挨拶をするか，または同様の挨拶を返せ。誠にアッラーは凡てのことを清算なされる。

Korean

너희가 인사를 받았을 때 그보다 겸손하게 인사하라 흑은 웅 답하라 실로 하나님은 모든 것을 세심히 헤아리시니라

[Translated from Uzbek++

When you are greeted with a greeting, greet with a better greeting or return it in return. Indeed, Allah is the One who takes account of everything.

 (The greeting in Islam is the most beautiful and meaningful greeting. In Islam, greeting ,those you know and those you do not know, is Sunnah. And returning the greeting is obligatory.)]