Throughout the ages the prayers of the righteous have shielded the Jewish People from much harm and have served as a conduit for success and salvation for countless individuals.
Moshe Stood Between G-d and the People
Moshe’s love for the Jewish People was so great that he even challenged G-d in an attempt to save them. After being informed by G-d that He wanted to destroy the Jewish People and start anew with Moshe and his descendants, Moshe, instead of agreeing, argued on behalf of the Jewish People. How does a human being challenge his Maker? With the purest of motives and genuine love Moshe stood between G-d and the Jewish People, shielding them from Divine retribution with his prayers.
Moshe declared, “And now, if You would please forgive their sin ― but if not, erase me now from Your book (the Torah) that You have written (Shemot 32:32).”
The Sun Stood at Givon
We also find that Yehoshua decreed and G-d answered him, as it is written, “Sun, stand still at Givon, and the moon, in the Valley of Ayalon. Then the sun stood still, and the moon stopped, until the people took retribution against their enemies. (Yehoshua 10:12-13)”
Revival of the Dead
So too with Eliyahu Hanavi, we find the great power in his words, as it is written:
“The son of the woman, the landlady, became ill. His illness became very serious, until there was no more breath left in him. She said to Eliyahu, ‘What is there between me and you, O man of G-d, that you have come to me to call attention to my sins, and to cause my son to die!’ He said to her, ‘Give me your son.’ He took him from her bosom and brought him to the upper story where he was dwelling, and laid him on his [own] bed. He called out to G-d and said, ‘G-d, my L-rd, have You brought harm even upon the widow with whom I dwell, to cause her son to die?’ He stretched himself out over the boy three times, and he called out to G-d and said, ‘O G-d, my L-rd, please let this boy’s soul come back within him!’ G-d hearkened to the voice of Eliyahu, and the soul of the boy came back within him, and he came to life.” (Melachim II chapter 4)