Interestingly in our lockdown times the rainbow has become a symbol of support for the NHS, and seems to have been naturally adopted by children as a universal symbol of thanks and hope. Walk through the housing estates and you will see home-make rainbow posters alongside the 'thank-yous' for our NHS and carers.
This seems to me to be appropriate: the rainbow is also the sign of God's covenant promises - a covenant made with Noah for all humanity and indeed all creation. It is a covenant of hope - of withholding forces of destruction, of limiting judgement. It is of course the covenant God declared to Noah after the receding flood (see Genesis chapter 9).
The rainbow is a symbol that reminds us that God would prefer mercy than wipe out.
In recent years the rainbow symbol has given at least some Christians a bit of a conundrum, because it has also been adopted by the LGBT community, its advocates and activists. Some may have been offended by this, perhaps seeing it as a hijacking of a Judeo-Christian symbol.
Yet it needn't be quite so problematic: I had noticed a trend for it to start to signify more than the LGBT labelling - broadening to respect diversity of many kinds. A kind of encouragement for each person to afford basic human dignity to every other person.
This broader usage surely also resonates with the covenant purposes of God: that whoever you are, wherever you are, God would prefer mercy for you along with the whole of humanity and creation rather than wipe out.
The rainbow sits deep in the Christian story, establishing a covenant that points to and connects with that other important Christian symbol - the cross - where justice and mercy meet, where wipe out is exhausted by grace.
So as Christians let us love rainbows! Wherever we see the symbol used, maybe it could prove to be a useful conversation starter about an greater topic.