What is the comparison to a tree?
Radak #1: One who veers from evil and does good, he is like a tree planted by water, which is always satiated. Also he is always happy with his portion, be it much or little.
Radak #2: The verse discusses the Brachah, Shalom and reward of one who veers from evil and does good. His reward will be to be like a tree planted by water.
Malbim: Man's power to sprout is like a tree whose roots are planted above, and its foliage leans down. Man's brain corresponds to the roots of a tree; from it go out all senses to the branches (limbs, and they return to it. A tree sends its moisture and food from the root to the branches; a person is different. A tree's life and source is in the ground. Man's Ikar is above - from there he receives his influence and life - "Al Kol Motza Pi Hashem Yichyeh ha'Adam" (Devarim 8:3). If "Al ha'Lechem Levado Yichyeh ha'Adam" (ibid.), and he turns only to the ground, he is upside down - his head below and his feet above. Tzadikim are like a tree 1 planted in a place of Taharah (above) and its foliage leans to a place of Tum'ah, and a Rasha is opposite (Kidushin 40b).
Malbim: A tree is unlike vegetation. Vegetation sprouts in summer; it brings out its flower and seed, and then it withers, and it is not. It keeps its species alive, but not itself. A tree lasts a long time. It brings fruits and its seed year after year. It keeps its species alive, and also it lasts many years; its fruits are for food, and its leaves for medicine. A happy man is like a tree. Most people do nothing to preserve themselves, only their species, and they leave their remainder to their children. The happy man, he will be fruitful also in old age (92:15); also he is preserved. His Kadosh fruit is Torah and good deeds that preserve his Nefesh. Also refer to 1:3:2:1, 1:3:4:5, 1:3:5:5.
What is the significance of "Shasul"?
Malbim: He is like a tree planted [from a sapling], and not Natu'a (from a seed). The latter was planted in its place; the former was uprooted from its place and replanted elsewhere to improve and fix it. There are fresh, moist herbs that cannot be replanted from place to place due to their great moisture. They will not improve or last long. A tree is not so moist. When one uproots it from its place and replants it elsewhere, it improves and lasts longer. "Ha'Yig'eh Gome b'Lo Vitzah;
What is "Al Palgei Mayim"?
Radak: It divides water; there is water on this side of the tree, and on this side. The water runs under the tree, and it is over the water.
Malbim: A tree planted in a dry place, it is troubled in drought years and ceases to produce fruits, or does not make them in their time. A tree planted by water always has its food and moisture. So those philosophers who are straight and conduct based on virtue and Chesed according to intellect etiquette, they will not always find their needs. Human intellect does not always hit the target; it usually errs. One who is planted on Toras Hashem and His commands, will always find his needs without error.
What is the significance of giving its fruit in its time?
Radak #1: A tree in a dry place thirsts for water. When it does not get enough water, it does not give its fruits in their proper time; they are delayed due to its thirst. A tree planted by water gives its fruit in its time.
Radak citing Avodah Zarah 19b: He gives Halachic rulings when he is qualified, and not beforehand. When his time comes, he does not refrain from ruling.
Radak #2: "B'Ito" teaches that at the time to learn, he learns; at the time to act, he acts.
Radak, citing Ibn Ezra: His fruit, i.e. the Neshamah of Chachmah, will be full of Torah and Chachmah of Elokim to recognize his Creator and His deeds that endure forever. It will cling in its higher world when it separates from its body, like a ripened fruit on a tree separates from it when it does not need it. The tree is for the sake of the fruit!
Malbim: It is not like vegetation, which merely produces seed to preserve its species. The tree gives fruits every year. It is not like a tree planted in a Midbar, which produces only inferior, ruined fruits. So a Tzadik is unlike the intellectual Nochrim who produce fruits (discoveries) via intellectual investigation. They are not fruits of the Nefesh that comes from the Divine; its fruits are Kadosh, and came via Hashem's Torah and its Mitzvos. "B'Ito" means that the tree produces the fruits in the proper time. So the happiness of the Nefesh and success of Tzadikim will be at its special time, when it returns to the place from which it was taken.
Lev Eliyahu (Shemos p.148): There is time for Torah, and time for Tefilah. If one engages in each in its proper time, "everything he does, succeeds"!
What is the significance of "v'Alehu Lo Yibol"?
Rashi (from Avodah Zarah 19b): Even his leftover is needed. The speech of Chachamim (even in secular matters) is needed, and one must [investigate to] learn [from] it 1 . Yibol is to wilt.
Radak #1: Leaves wilt due to dryness. This will not occur to this tree. "B'Ito" applies also to this. The leaves will not wilt in summer, the time when they are needed for shade. Travelers will find relief from it - they will rest under its leaves, drink the water under it and eat its fruits. However, in winter, most trees drop their leaves.
Radak #2: Even in winter it will not drop its leaves, like we find in a minority of trees due to their great moisture - "Lo Yibol Alehu v'Lo Yitom Piryo
Radak: One learns from it Musar of the world, and how people should conduct with each other.
What is the meaning of "everything he does, succeeds"?
Radak: If one takes a branch from this tree (and grafts it), it will succeed and be like it (the tree from which it was taken). So a good man, his sons and offspring are like him.
Radak citing Avodah Zarah 19b: If he engages in Torah, his property succeeds for him.
Radak, citing Ibn Ezra: His wealth, children and honor will succeed.
Malbim: Also the seed of this tree will succeed. Everything seeded or planted from it will be like it. So a Tzadik, his sons succeed in his merit. They will be Giborim in the land; a straight generation is blessed.
