Yohanan ben Zakkai allegedly said the following:
“If you are holding a sapling in your hand and someone tells you, 'Come quickly, the Messiah is here!', first finish planting the tree and then go to greet the Messiah.”
Apparently the quote above appears in Avot D'Rabbi Natan 31. However, I was unable to find such a quote. I'm guessing the quote is found in variant B of Avot D'Rabbi Natan. Where may I find/read this variant and this quote?