Want of a nail

This is a well known nursery rhyme

For want of a nail the shoe was lost,
for want of a shoe the horse was lost,
for want of a horse the knight was lost,
for want of a knight the battle was lost.
So it was a kingdom was lost – all for want of a nail.

The Oxford Dictionary of Nursery Rhymes gives as the oldest version the words of Adams in his complete sermons of 1629

“The want of a nail loseth the shoe, the loss of a shoe troubles the horse, the horse endangereth the rider, the rider breaking his rank molests the company so far as to hazard the whole army.”