Why does it say "v'Ra'isi"?
Ri Kara: Since I see that everything returns to the earth, there is nothing better than to rejoice in his deeds in his lifetime.
Metzudas David: I saw intellectually.
Is this the only good?
Rid: It is the only way to receive his portion in this world.
How should one rejoice in his deeds?
Rashi: He should rejoice in the fruits of his toil. He should rejoice and eat, and not desire to get rich.
Ibn Ezra: People who think that they are like animals, there is nothing better for them than to rejoice in their lifetimes. They have no other portion. Why should they engage in things that they will leave after them?
What is "Chelko"?
Rashi: The fruits of the toil of his hands. Shamayim gave this to him; he should rejoice in it.
Ri Kara: His Simchah in his deeds. The rest, others will inherit it. If you will say that rather than rejoicing over his deeds, he should be sad that his property will pass to his sons, and he does not know if they will be wise, and it will stay in their hands - I answer, he should rejoice in his world, and not be sad over what will be after him.
What is the meaning of "Mi Yevi'enu Lir'os b'Meh she'Yihyeh Acharav"?
Rashi: After he dies, who will bring him to see if his children succeed with the wealth that he gathered and left to them, or they will not succeed?
Rid: [Who will show me] what I will leave for my son after me?
Metzudas David: His Simchah in this world is only what he eats, for after he dies, who will bring him to see the Simchah and good of his children with the wealth that he left to them?