The Bible, from the beginning line, assumes God, so, as a Christian believer, I will not be defending the idea, existence or character of God - the God of Abraham, Isaac and Jacob, who is the same God and Father of our Lord Jesus Christ.
A long, long, long, long time ago, God called this man Abram, as in: spoke to, said, told, directed -verbally or in a dream (the Bible does not say) - and told him to stop worshipping other gods, pack up his stuff, and leave for somewhere else - Go into the Wild.
Now, nomadic people of the Ancient Near East were not unknown for having gods, dreaming dreams, or wandering about near and far. That this specific record comes down to us thousands of years later is significant, and worth reading from Genesis 11:27 through to 12:9.
Abram received both call and promise from God. The call was to hear and obey the instructions of the One who made the heavens and the earth - the One who knows all, sees all, and whose ideals are to be followed. The promise was a huge, unusual and far-reaching prospect: to be the father of many nations (when he and his wife were old and childless), to possess land (when he was of a nomadic tribe and culture), and to be a blessing to many (who? how? what? when?).
Abraham - his name changed and his nature being transformed - obeyed God, and this was the overall summation of his life, even though specifically, he stuffed up badly and often.
[Read the story!]
His wife, Sarai, whose name was also changed - to Sarah - had to come along too, as there was no such thing as lone, independent women in those days. Her story is enmeshed with that of Abraham: she lies as connives as much as he does; treats Hagar horribly after using her as a surrogate; laughs at the thought of a promised child knowing that old age was a great encumbrance to the action and the passion, and, seems to be a bit negative if not nasty. She was, like Abraham, a 'normal', fallible, sinful human being.
But God (my two favourite words in the whole universe!!!!) intervened, and patiently and lovingly drew these two wanderers by his name and by his word.
God's grace to fallen humanity is clear in his treatment of this foundational Bible couple. God does not strike them dead after their lies, after Sarah's laugh (and lie about it) - after all, the purpose of God is to show himself great in the light of human weakness. The purpose of God is to let us see our darkness and sin and so run to him for grace, mercy and forgiveness.
And so Sarah died, as we all must, and Abraham purchased with gold the first patch of promised ground, Ephron's field near Mamre: "both the field and the cave in it, and all the trees within the borders of the field" (Genesis 23:17). Abraham buried Sarah in the cave and mourned under the trees for the allotted period of time, as per ancient customs.
The Wild was being changed by the tears of the father.
Those trees and many others of the promised land, would be watered with much more blood, sweat and tears as time went on.