KJV : And I say <0559> (8799) unto thee, Let my son <01121> go <07971> (8761), that he may serve <05647> (8799) me: and if thou refuse <03985> (8762) to let him go <07971> (8763), behold, I will slay <02026> (8802) thy son <01121>, [even] thy firstborn <01060>.NASB : NASB# : "So I said<559> to you, 'Let<7971> My son<1121> go<7971> that he may serve<5647> Me'; but you have refused<3985> to let<7971> him go<7971>. Behold<2009>, I will kill<2026> your son<1121>, your firstborn<1060>."'"