Masechet Avot, Perek Gimel, al (on) Mishnah Zayin. The Mishnah says that this rabbi said, “Ten lo mishelo, she'ata v'shelcha shelo.” Give Hashem what is His.
If you give of yourself and of your possessions to do the will of Hashem, you have to, because you and what you own really belong to Hashem. You’re really His in the first place. You have no right to hold back yourself or your possessions from doing the mitzvot (commandments), because in reality everything belongs to HaKadosh Baruch Hu (the Holy One, Blessed is He). So give of yourself and of your possessions. Give your body, your spirit, your energy, your time, and the talent that you have. In reality, don’t give yourself too much credit, because it’s really Hashem. Hashem gave you all of those gifts, and they’re meant to be used in the service of HaKadosh Baruch Hu. So give back as much as you can.
In a prayer stated by David HaMelech, we say, “Everything is from you, Hashem, and it’s from your hand that we have given to you.” So we’re basically giving Hashem back what He gave us.
If there are people traveling on the road and studying Torah, and a person interrupts his learning and says, “How beautiful is this tree, how beautiful is this plowed row of produce, of produce,” Torah says that this person is liable for putting his life in danger. He stopped his Torah study to praise nature, to praise the world. A person’s Torah study—even though here he’s praising the creations of Hashem—he’s not doing something that’s purely mundane. He’s praising the creatures of God. Bottom line, a person who stops his Torah study is doing something negative, and therefore he’s putting himself in danger.
The derech, the road, is a dangerous place to travel, and what’s sustaining this person, possibly, is his Talmud Torah, his Torah learning. So when a person stops his learning and praises a tree, he’s doing something that could possibly cause him a problem, cause him some danger.
Others explain. Rav Kook explains this Mishnah as a person compartmentalizing. Here we’re inferring from the word u-mafsik mi-mishnato: he stops his learning and praises the tree. He doesn’t view the praise of the tree as part of his Torah learning. He views that as nature, as part of his Torah learning. And the Torah is for the Beit Midrash (study hall). Torah is for the synagogue, but whatever else happens in the world, that’s not Torah to him. In reality, if he didn’t stop his learning, if he viewed praising the tree as part of his learning, it wouldn’t be such a negative thing.