The duty to acknowledge kindness received from another is called hakarat hatov. Lehakir means to recognise or familiarise oneself with something; tov, goodness.

The obligation to be makir tov is not merely to remember to say thank you, but to actually take time to recognise the benefit one has received from another. We are commanded not to despise the Egyptian for you were a stranger in his land (Deuteronomy 23:8). We owe a debt of gratitude even to our oppressors for the small kindness they may have done for us.

Hakarat hatov extends to inanimate objects as well. Moses famously did not strike the Nile to catalyse the plague of blood for that would have shown a lack of gratitude to the water which had conveyed him in his ark to Pharoahs daughter.

A modern-day example is of the late Rabbi Yisrael Zeev Gustman, head of Yeshivat Netzach Yisrael, who used to water the bushes in front of the yeshivah. For when fleeing Vilna, he had hidden behind some bushes and always felt a debt of gratitude to them, be they in Vilna or Jerusalem. Neither Moses nor Rabbi Gustman credited water or bushes with the will to chose to save them, but they recognised that to destroy or disregard something that once helped you is indeed a base trait.

The notion of hakarat hatov towards nature is a form of Jewish environmentalism. How can we continue to damage the natural world when it has given us so much?