The Gemara asks: what gives the soldiers the strength and success to be victorious in war? Rebi Yehoshua Ben Levi answers: when there are people learning Torah on their behalf. (Makkot 10)
David Hamelech wouldn’t go to war unless the Rabbis gave him permission so that they would feel obligated to pray for the soldiers' success. (Berachot daf 3:)
Even though David Hamelech would ask the Urim Vetumim and knew that he would win the war, David still wanted the Rabbis to pray for him. Even though he knew he would win the war, he was still concerned for casualties. Therefore he wouldn't go to war unless the People were going to pray for the soldiers.
The Midrash says: for every soldier that was in David Hamelech's army there was a designated person who would pray for his safety and success. (Rabbah Bamidbar perek 22)
This site is meant to pair soldiers up with others who will make sure to pray and learn constantly to give the soldiers an assurance that they will come back victorious. At a time of war we all need to feel the pressure to do more for the sake of our brothers who are fighting our battle.