God's Faithfulness, The Rainbow & Israel's National Perpetuity
When we see a beautiful rainbow, we are reminded of God's faithful character.
Why?
Because God is using the rainbow as an instrument, a sign, to remind us that He will never flood the whole earth again.
"I have placed My bow in the clouds, and it will be a sign of the covenant between Me and the earth." - Genesis 9:13
Does God employ other elements of creation to teach us about His covenant faithfulness?
Yes, Jeremiah 31 teaches us that God is also employing the sun 
the moon 
the stars 
and the oceans 
as instruments, signs, that point to His faithfulness! These are called "the fixed order."
Faithfulness toward what or whom?
Let's read the passage together from Jeremiah 31:35-37:
This is what the Lord says:
The One who gives the sun for light by day,
the fixed order of moon and stars for light by night,
who stirs up the sea and makes its waves roar —
Yahweh of Hosts is His name:
If this fixed order departs from My presence—
this is the Lord’s declaration—
then also Israel’s descendants will cease
to be a nation before Me forever.
This is what the Lord says:
If the heavens above can be measured
and the foundations of the earth below explored,
I will reject all of Israel’s descendants
because of all they have done—
this is the Lord’s declaration."
So, God wants us to see the natural order and remember that He will preserve Israel, regardless of their behavior or belief?
That's right! The preservation of Israel is not about their merit or belief. God has set them apart for His own purposes, for His own glory.
So, what do I tell people that say God has moved on, rejected, transferred or already fulfilled Israel's purposes?
Just point to the skies or the oceans, just as God did with Abraham in Genesis 15. Use the natural order to teach about God's covenant faithfulness. And of course, graciously point them to Scripture.