The usual greeting is : السلام عليكم / السلام عليكم ورحمة الله وبركاته as-salamo alaykom / assalamo alaykom wa rahamato allahe we barakatoh Peace be upon you / Peace be upon you and Allah's mercy and blessings and when somebody asks you how you are he would say كيف حالك Kaifa haluk How are you ? and you could reply him الحمد لله بخير al hamdo lellah bekhair Thanks allah I am fine Blessings بارك الله فيك barak allaho feek God bless you You can say it to someone who has done a favor for you كان الله في عونك kana allah fe awnek God be with you you can say it to someone who is facing some troubles يرحمكم الله yarhamokomo allah God bless you you can say it to some one who has just sneezed إن شاء الله In shaa allah God willing You can say it before future tense For example : سوف أذهب إلى مصر إن شاء الله I will go to Egypt god willing