My family in Christ, shalom.
Thanks for rejoining me on my journey through the Bible. Last time we saw how Sarai’s frustration led Abram to have a son with one of her female slaves, Hagar. In this post we will see how, thirteen years later, Abram and his entire caravan are given cause to celebrate, for their long wait is nearly at an end.
At the opening of chapter 17 the 99-year-old Abram is still childless. Can anyone among us imagine the rising tide of utter frustration that must have been at the back of his mind? It seemed that one god among many had promised him and his barren wife a son in their old age, and now almost 30 years later the promised progeny still hadn’t materialised. Was Abram expecting anything more now than yet another empty promise? When God appeared again, what He said sounded so familiar:
“You shall be the father of a multitude of nations”
(v. 4b JPS).
How Abram must have hated hearing this! But this time the LORD started off His discourse differently. He introduced Himself as El Shaddai, literally God Almighty. This patriarchal family had already ecountered a variety of names for the LORD, and a lot more would be revealed to future generations.  Over the coming centuries these titles would be used over and over again in worship and praise. Here is a good example:
God Almighty declared that He is now ‘making’ a covenant (agreement) with Abram. (There is however no room for negotiation. But Abram seemed not to mind as he ‘trusted’ the LORD). For His part, God now bestowed new names on the patriarchal couple. Abram (‘high father’) was now to be known as Abraham (‘father of many’), as his previous priestly role was now to be chanelled into parenthood. It seems to me that Sarai’s name was no longer to suggest that she was simply her husband’s princess (‘my princess’). Rather, she was now called Sarah, the eminent mother of a blessed dynasty (‘lady’, ‘princess’, ‘noblewoman’) (vv. 5, 15):
“I will bless her; indeed, I will give you a son by her. I will bless her so that she shall give rise to nations; rulers of peoples shall issue from her”
However, Abraham laughed uncontrollably at this. Weren’t they both too old to be parents (v. 18)? I suggest that Abraham’s doubt at this point may just come about from a mixture of excitement and disbelief. Now, after 30 years of ‘wondering’ (which he started when he had been 70 and Sarah 60), things were finally happening. Could it actually be true or was it just a cruel trick? Oh how his bones must have been aching!
It seems as if he did not want to entertain the notion and be let down again, and he suggested that Ishmael should be the one to further God’s plan (v. 18). But as we have seen in past posts, the LORD’s plan included both Abraham and Sarah, and this time the LORD delighted His servant with a date:
“…Sarah shall bear [Isaac] to you at this season next year”
(v. 21). 
Oh what joy! The long wait was nearly at an end. But agreements are two-sided affairs, and Abraham had not yet heard what he must sign up to. The posterity of Abraham’s seed is conditional upon the circumcision of every male (sons, homeborn and foreign slaves) from now on.
Abraham agrees and at 99-years-of-age he was circumcised on that very same day. So too was his 13-year-old son Ishmael, his homeborn and foreign slaves, and all the other male members of his caravan (vv. 23-27). Within a world of sin there now existed a small, faithful, God-fearing nation which now had an explicit, covenanted agreement with God and a developing view as to its purpose and to how it will proceed.
In the same way that circumcision did not save a person,  an issue highlighted by the periodic need to sacrifice lambs and other creatures (e.g. Luke 2:24), this has be replaced in Christian circles by the belief in Christ’s atoning sacrifice and the repeated reception of His cleansing blood (1 Corinthians 11:23-26).
I do hope that these short notes have been of some use to you, and that you will join me again soon.
Shalom and God bless you.
 For example, El-Elyon (‘God Most High’, 15:19-20) and El-roi (‘the God who sees me’, 16:11). For a more extensive list of names see here.
 However, God will not completely cast aside Ishmael, and has a plan for him as well which we shall explore in a future post.
 In Gen.15:6, assuming that we can apply this generally, it is trusting in God which saves a person. Circumcision is only a part of it, as for a Jew trusting God means faithfully applying His covenant.