Ki Tetze (when you go) out to war

When you go out to war

Deuteronomy 21:15 If a man has two wives, הָאחַת the one loved and the other hated and they both bear him children and if the firstborn son is from the woman who is hated: 16 Then when it comes time for him to pass his inheritance to את־ his sons את which he has may not begiven to the firstborn את־ son of the loved wife before the firstborn son of the hated wife: 17 But את־ the firstborn son of the hated wife, he will acknowledge by giving him a double portion of all that he has: because he is the firstfruits of his manhood; the right of the firstborn is his. C-MATS

Question: What is a double portion? The firstborn son takes a share equal to that of two brothers together. If a man with four sons divided up his inheritance, he divided the inheritance into five equal shares, giving two shares to the firstborn and one share to each of the other three sons. Chumash

Question: What are the rights and responsibilities of the first born? The position holds great honor and responsibility.