Hi Violet - I will give my two cents (and I am no theologian.  I have no degrees.  Just one who can't put down scripture and was called to priesthood in my youth and fights for justice now.)   I will try to address each of the parts you wrote as I believe they are all important sections. 

Abraham with Sarah (God views them as one complete creation, from what I read, though this does not indicate they have specific responsibilities in marriage due to gender) firstly are promised that his offspring will be the chosen & exceptional people.  God keeps his promise and so we see David sing of the promise from God to him that his offspring too will be judged by his own blood:  Ps. 122:4-6 -To which the tribes go up, even the tribes of the LORD-- An ordinance for Israel-- To give thanks to the name of the LORD.  For there thrones were set for judgment, The thrones of the house of David. Here in psalm & in small spots in Kings we see this promise to Samuel and it carries on into the Gospels.