Abraham was a hundred years old when his son Isaac was born to him

Genesis 21:1-34
Sarah became pregnant and bore a son to Abraham in his old age, at the very time God had promised him. Abraham gave the name Isaac to the son Sarah bore him. Abraham was a hundred years old when his son Isaac was born to him.
But Sarah saw that the son whom Hagar the Egyptian had borne to Abraham was mocking, and she said to Abraham, “Get rid of that slave woman and her son, for that woman’s son will never share in the inheritance with my son Isaac.” 
The matter distressed Abraham greatly because it concerned his son.  But God said to him, “Do not be so distressed about the boy and your slave woman. Listen to whatever Sarah tells you, because it is through Isaac that your offspring will be reckoned. I will make the son of the slave into a nation also, because he is your offspring.”
After the treaty had been made at Beersheba, Abimelek and Phicol the commander of his forces returned to the land of the Philistines. Abraham planted a tamarisk tree in Beersheba, and there he called on the name of the Lord, the Eternal God. And Abraham stayed in the land of the Philistines for a long time.
Beersheba can mean well of seven or well of the oath.
Twenty-five years have passed since the promise was first made. Isaac's elderly parents are naturally overjoyed at his birth. Sarah's demand that Hagar and Ishmael be sent sway runs counter to custom, and Abraham needs a word from God before he will agree. Galatians 4L22 shows why the rift was inevitable. God's care for Ishmael, although he was not the child of the promise, once more shines through. Outcast by Sarah and Abraham, he is not cast out by God. On the contrary, 'God was with the child as he grew up'
Water has always been precious to the herdsmen in the dry climate of southern Palestine. Monthly rainfall in this area drops from 100mm in January to nothing at all in the four summer months. So Abraham's dispute over the well at Beersheba is not surprising. Abimelech may be a Philistine title for 'king', rather than a personal name.
Why?
God's promise comes true 25 years later. SO the word of the Lord is always true.
Because Ishmael is the offspring of Abraham, God's blessing is with Ishmael.
Sarah get away Hagar and Ishmael seem envy foreigner to share his heritage, but it is God's blessing that this is the blessing to God's people, Israelite.
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1.亞伯拉罕兩個兒子如何處理?
   撒拉從暗笑到喜笑。經歷了神的應許。怎麼才能領受恩典，領受恩典要如何使恩典維持下去。
2.神如何指引
    撒拉的想法雖然是出於自私，但是卻與神一樣。以實馬利是人的錯誤留下的痕跡，也不要讓錯誤的結果影響到神作為的干擾。舊的不能影響新的。以實馬利是人的方法生的，以撒是神的作為生的。如果留下以實馬利是留下靠自己的作為。我們不能一邊靠人一邊靠神。亞當用葉子遮羞自己的羞恥，人用功德、苦行想來遮掩自己的罪。神要人將這些人為的遮蔽攝去，不顧面子在神面前是何等羞恥、不配的。不能又用自己的方法，又用神的方法，最後一定是人的方法會取代人的方法。以實馬利是爭戰的，以撒是安靜的，屬神的。趕出以實馬利、夏甲要很大的決心，放下我們目前擁有的很難。趕出去以人的想法來看真的沒有愛、沒有親情、很殘酷。怎麼忍心。但是這都不是理由。神會看顧、帶領。放下來的神會自己成全。
3.亞伯拉罕令人折服
   敬畏神的人，令亞米比勒折服。在夏甲的處理後，神要賜亞伯拉罕土地。一個有軍隊、有權勢的人，居然要和一個弱小的國家來求和、立約，除非他們看見這個國家，這個人背後有很大的靠山。
我們希望別人看重台灣、強化軍隊、發展經濟都沒有用。敬畏神, 沒有軍隊，沒有經濟, 才是讓人尊敬我們的方法
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How?
God's promise never fails, God's word is my way and blessing.