Parashat Ki Tavo-Felicidad en los Bikurim

And you shall enjoy, together with the [family of the] Levite and the stranger in your midst, all the bounty that your God יהוה has bestowed upon you and your household.

ושמחת בכל הטוב AND THOU SHALT REJOICE IN EVERY GOOD THING — From this they (the Rabbis) derived the law that the recital on the occasion of bringing the first fruits is made only during the joyful period of the year — from Pentecost till the Feast of Tabernacles — when a man is gathering in his grain, his fruits, his wine and his oil; but from Tabernacles onwards until Chanucah if he brings these, he does not make the recital (Pesachim 36b).

And you shall be joyful That in the merit of this, the Omnipresent will make you joyful. And our teachers explained (Pesachim 36b, Bikkurim 1:6) that at the time of joy - from Atzeret [Shavuot] until Chag [Sukkot] - one brings and reads. For that is the time of picking fruit, and people are joyful. From thence onwards, one brings and does not read. And a ger brings and does not read, because they cannot say "fruit of the land You gave me" (Devarim 26:10) "that God swore to our ancestors" (Devarim 26:3) - for they do not have a portion in the Land. And in Masechet Bikkurim (1:4) they say, Since they cannot say "to our ancestors" - and so in prayer, since in prayer our teachers relied on the Talmud Yerushalmi [Bikkurim 1:4 (2:2)] that they bring stories that gerim said in prayer "God of our ancestors". This is because "our ancestors" [אבותינו avoteinu] is the language of "our great ones" [גדולינו gedoleinu], like "And He has set me as a father to Paroh and as a master to all his house" (Bereishit 45:8), and so too "he was the father of all those who play the lyre and the pipe" (Bereishit 4:21), which is translated (Targum Onkelos on Bereishit 4:21) "their teacher" [רבהון rabhon]. And so "father of many nations" (Bereishit 17:4) - prince and master of the whole world. And thus the geirim are accustomed to say "God of our ancestors" in prayer, and this is primary.