We have finished siman 6, and are discussing zmiros on shabbos. Today, we will discuss reciting shaim Hashem in zmiros.
The discussion of reciting shaim Hashem out of the context of a pasuk is discussed by the Mishnah Berurah in the Biur Halacha in siman 188. If a person forgot to recite Yaaleh Veyavo in birchas hamazon, and missed the opportunity to recite the special bracha for one who remembered right after boneh yerushalayim, the question is whether it can be added in the harachamans. The Shulchan Aruch writes that if one forgot Al Hanissim on Chanukah or Purim, it can be added into the harachamans. The question is whether one can do the same for Yaaleh Veyavo. The Rema writes that one should not do so, because Yaaleh Veyavo is different than Al Hanissim in that Al Hanissim has no mention of shaim Hashem, but Yaaleh Veyavo does. Therefore, the Rema concludes that to add Yaaleh Veyavo into the harachamans would not be appropriate.
The Magen Avraham questions why there should be any issue inserting Yaaleh Veyavo in the harachamans. Even though the harachamans are bakashos rather than tefillos, he does not see any issue with reciting shaim Hashem in a bakasha. The Biur Halacha quotes the Magen Avraham and finds the Rema’s opinion difficult as well. Even though Chazal never instituted a specific nusach for Yaaleh Veyavo to be recited in the harachamans, the Biur Halacha does not see an issue with reciting such a harachaman with shaim Hashem. Apparently, we see that one does not need a nusach composed by Chazal to recite shaim Hashem. The Taz concurs with the Magen Avraham, writing that he does not see why any time one recites the shaim Hashem as part of a bakasha it should be acceptable.
However, the Shulchan Aruch Harav writes that if there is no need (i.e., Chazal did not require one to recite the shaim Hashem), one should refrain from reciting the shaim Hashem. If so, we seem to have a machlokes whether one can recite the shaim Hashem in a tefillah which was not instituted by Chazal. Reciting the shaim Hashem in a bracha which was not instituted by Chazal is even more complicated, as we have a concern of a bracha levatala. However, the consensus of the poskim is that reciting the shaim Hashem as part of a bakasha is muttar, even if the bakasha was not instituted by Chazal.
Regarding saying shaim Hashem as part of a shira or hodaah (praise or thanksgiving) to Hashem, the Chazon Ish writes that it is muttar, and there is no problem in doing so. The Kaf Hachaim discusses this question in siman 215, and writes that it is only appropriate if they recite shaim Hashem with the proper eimah v’yirah (fear and trepidation) required when reciting shaim Hashem. If one will end up reciting shaim Hashem in a lighthearted or joking way, it is inappropriate.
Therefore, if one is singing zmiros, and is focusing on the shaim Hashem when they reach it, it is appropriate to recite shaim Hashem. However, if one is just enjoying the singing, and not contemplating the words, it is inappropriate to recite shaim Hashem.
One of Rabbi Reingold’s rabbeim did not recite shaim Hashem in zmiros. He would say that the halacha is that when one recites shaim Hashem they are (lechatchilla) supposed to have proper kavanos, as is brought down in Orach Chaim siman 5. He would say that the shaimos of Hashem which one has to say (in davening and brachos and the like) are hard enough to recite with proper kavanah, so it seems illogical to add more shaimos. Although this is not a halachic requirement, it is certainly an appropriate thought process.
Summary
If one will have appropriate kavanah when reciting shaim Hashem in zmiros, they may recite shaim Hashem. However, if they are not focusing on the shaim Hashem, it is more appropriate not to recite it.