Commentary for Berakhot 69:3
והאי קדש הלולים להכי הוא דאתא האי מיבעי ליה חד דאמר רחמנא אחליה והדר אכליה ואידך דבר הטעון שירה טעון חלול ושאינו טעון שירה אין טעון חלול וכדר' שמואל בר נחמני א"ר יונתן דאמר ר' שמואל בר נחמני א"ר יונתן מנין שאין אומרים שירה אלא על היין שנאמר (שופטים ט, יג) ותאמר להם הגפן החדלתי את תירושי המשמח אלהים ואנשים אם אנשים משמח אלהים במה משמח מכאן שאין אומרים שירה אלא על היין
Surely it is required [to teach as follows :] First, that the All-merciful declares [the owner] must redeem it and then eat it ; and second, only those things which require "a song of praise" require redemption, but if they do not require "a song of praise," redemption is unnecessary ! This is according to the statement of R. Samuel b. Nahmani in the name of R. Jonathan who said : [not translated] Whence is it that we say "a song of praise" only over wine ? As it is said, "And the vine said unto them, Should I leave my wine which cheereth God and man?" (Judges ix. 13). If it cheereth man, how does it cheer God ? Hence it is to be inferred that we have "a song of praise" only over wine.
Tosafot on Berakhot
If so, this rule as well, that one must redeem fruits of the fourth year before eating them should be derived from מעשר שני via the same common word system. Why do we need the word הלולים at all to teach us that fruits of the fourth year must be redeemed? And we can answer: if not for the verse הלולים, I would say that the reverse is true, we should derive a stringency via the system of a common word, the word קדש that appears in reference to the fruits of the fourth year from the word קדש3כי יובל הוא קדש תהיה לכם מן הדשה תאכלו את תבואתה: that appears in reference to shmeetoh, and there should be no redemption allowed for the fruits of the fourth year. Just as there is no possible redemption of the fruits of sh’meetoh, so too, there should be no redemption of the fourth year fruits and they must be brought to Jerusalem to be eaten. It is because we have the word הלולים that we know to make the more lenient derivation from מעשר שני.
Tosfos suggests another way of answering his original question. Why is the word הלולים needed, when we have the common word קדש that can be used as a source that fourth year fruit needs to be redeemed?4In order to avoid confusion we must keep in mind that the term fourth year fruit means that it is the fourth year since they were planted. The nuber of the year has nothing to do with the shmeetoh cycle. Thus fourth year fruit can happen at any time of the shmeetoh cycle. It should not happen on the third year, since that would mean that it was planted during the shmeetoh year which is forbidden. Alternatively, Rabainu Chaim Kohain Said that if the source would be the redemption of מעשר שני, I would say that it is totally like מעשר שני. And only at such time that מעשר שני is in effect such as in the first, second, third and fourth years of the shmeetoh cycle is the redemption of fourth year fruits in effect. However, during the third and sixth years when there is only מעשר עני I might say that fourth year fruits cannot be redeemed, therefore the Torah taught us the word חלולים that teaches us that during all years of the shmeetoh cycle one may redeem fourth year fruits.