This individual was quoting the Tzemach Tzedek (3rd Lubavitcher Rebbe) who is quoted in HaYom Yom 24th of Shvat:
"If you only knew the power that lies in the verses of Tehillim and their effects in the celestial heights, you would recite them all the time. Know that the chapters of Tehillim break through all barriers and soar aloft from level to level unimpeded. They intercede before the Master of the Universe and secure their effect with kindess and mercy."
In his diary (see Tehillim Ohel Yosef Yitzchak p. 210), the Rebbe Rayatz (6th Lubavitcher Rebbe) relates a story surrounding this statement that is to long for me to type.
The summary is as follows. The Tzemach Tzedek saw in a vision a very harsh decree against the Jewish people, especially the Torah community. Nothing could overturn in. The Tzemach Tzedek told his oldest son to get a minyan to say the entire book of Tehillim no later than 4am. For 53 days the minyan took place and then the Tzemach Tzedek had a vision of his grandfather the Alter Rebbe holding 53 books of tehillim smiling.