Tafsiran Mazmur 72:16: Rashi & Radak

May there be an abundance of grain Heb. פסת, an expression of spreading (פסיון), increase and abundance. Our Sages, however, explained this as an expression of loaves of white bread during the messianic era (Keth. 111b, Shab. 30b), and the entire psalm as referring to the messianic era. Another explanation: פִּסַת is an expression of good will, like פִּיוּס, placating; the people are appeased and accepted by the Holy One, blessed be He, when He gives plenty in the world.

May there be an abundance of grain – In the days of this king there will be such blessing in the world that if one plants a handful of seed, even on the mountain tops, the grain stalks will be so good and healthy that they will shake in the wind like the cedars of Lebanon. Its fruits – This means the fruit of a handful of seed:

may its fruit rustle like Lebanon May the wheat kernels be as thick as the kidneys of a large ox, as happened in the days of Shimon ben Shatach.

and they will blossom forth Israel.

from the city From the midst of Jerusalem like the grass of the earth.