Why does it say "v'Gam"?
Ibn Ezra: Also this, to rejoice, one can do so only if the time is proper from Hashem, according to what Hashem gave at the beginning of creation.
Seforno: Also this is known [that if one will get enough to eat and drink, i.e. needs of temporary life?]
Metzudas David: Also one who did not realize this from his own Da'as, rather, his nature veered his heart [to do Chesed and Tzedakah].
What is seeing good in his toil?
Rashi: It is Torah and Mitzvos.
Seforno: He attains good in investigation, and in deeds.
Metzudas David: He does Chesed and Tzedakah with the wealth that he attained via his toil.
What is "Maatas Elokim"?
Refer to 3:13:1:1.
Rashbam: Shamayim gave to him a time and a Mazal to do go for himself.
Ri Kara: Only this Hashem gave to him - to eat and drink from his property. The rest will remain, and others will consume it.
Seforno: Hashem helped him to get what suffices for him.
Metzudas Tziyon, Metzudas David: It is an expression of Matanah (a gift), that Hashem made his nature like this.