One who completes the Book of Tehillim before his tefillah may, on the days when the complete Hallel is recited with a berachah, recite the berachah on the Hallel.
Sources and Explanations
The Minchat Elazar (vol. 3, siman 34) grappled with this question. Since the mitzvah of reciting Hallel is a rabbinic obligation, and it is known among the poskim that, according to all opinions, a rabbinic mitzvah does not require kavanah, as cited in the Magen Avraham (60:3), it would follow that when one says Tehillim before the tefillah and says Hallel there, upon reaching it in its order, he automatically fulfills his obligation, since no intention at all is required to fulfill it. How, then, can he afterward recite a berachah on the Hallel during the tefillah, since he has already fulfilled his obligation? After a lengthy responsum he concluded that one who reads Tehillim before the tefillah on days when the complete Hallel is recited has a kind of contrary intention (an intention not to fulfill the obligation). He writes (s.v. Ulam): “It can be said that when he says Tehillim before the tefillah, since the practice is to say them afterward during the tefillah with a berachah together with the tzibbur, and he said them during the Tehillim without a berachah, he has revealed his mind that he does not want to fulfill the obligation, and it is like a contrary intention not to fulfill it at that time, and he can afterward recite the berachah on the Hallel (and with a contrary intention, all agree that one does not fulfill the obligation, as the Ran writes).” He brought proofs for this principle, and therefore he may afterward read Hallel with a berachah.
The Chashukei Chemed (Shevuot 15b) also cited his words, and added an answer of his own: the manner of reciting Tehillim is not similar to the manner of reciting Hallel, for the chapters of Tehillim that he said before the tefillah he said as a plea for mercy and appeasement, and therefore he does not exempt himself from reciting the Hallel, whose essence is thanksgiving to Hashem. Indeed, in these words he arrived at the same point as the Magen Avraham (beginning of siman 584), whose words were cited in the above responsum of the Minchat Elazar (and we cited his words in the halacha dealing with one who reads Tehillim every day).
From the sefer “Shaf Veyativ – Laws of Saying Tehillim” by Rabbi Shay Tahan, Chapter 7: What Is Forbidden and Permitted When Saying Tehillim, Halacha 22 (p. 132 in the print edition). Translated from the Hebrew original.
