In Parashat Ki Tavo, Moshe goes into detail regarding this commandment with half the nation standing on Mount Gerizim and the other half on Mount Ebal and the Levites standing between the mountains reading the blessings on Mount Gerizim and the curses on Mount Ebal, and the entire nation responding with Amen.
This ceremony of giving the blessings on specific mountains seems odd at first. What does Mount Gerizim have to do with blessings and how is Mount Ebal connected to curses? Is there any significance to giving blessings or curses on mountains, on earth, even if the people are standing on them?
Rabbi Samson Raphael Hirsch (a great commentator who lived in Germany about 150 years ago) noted the great difference between these two mountains which are situated to the north and to the south of the city of Shchem. Seemingly, these mountains resemble each other and are in a similar topographical area. Their heights are similar as well, with Mount Gerizim rising to a height of 881 meters while Mount Ebal rises to a height of 940 meters. (Note ? there are sages of the Talmud Yerushalmi who were unsure that these mountains are the biblical ones, but this is the accepted opinion.) These two mountains rise above the same earth and the same rain and dew water them both. The same air and pollen hover over both. In light of this, the difference between them is noticeable. Mount Gerizim is covered in flora to its very peak. It is alive and beautiful. However Mount Ebal is notably barren, lacking vitality and growth.
Because of this marked distinction, the blessings were placed on Mount Gerizim and the curses on Mount Ebal. This emphasized for us that blessings and curses are dependent on us. We must not think that external reasons cause a person to be happy and blessed, to be righteous or successful. We must not believe that if we did not merit wisdom or wealth, beauty or power, we cannot succeed in the world. We must comprehend that each and every person?s success depends only on him.
Just like the mountains had the same external assets but different results, so with a person ? his external factors do not lead to him being blessed or cursed, but rather his own deeds do.
If we choose to let momentary desires and varying impulses guide our path and blow us in different directions, we will not be able to choose blessings. But if we move ourselves forward and direct our ambitions toward the proper moral path, if we consistently walk in the path which is deemed the correct path in the eyes of G-d and man, we will enjoy infinite joy and blessings.