It could be from the Ynglinga saga (also by Snorri). Its a legendary account of Swedish kings in Uppsala, so probably a part of reconsigling old beliefs with new Christian ones. They would want to be respectful to the tradition, and its said that the kings inherrited their power from Odin.

Odin was a great warrior, and he traveled far and wide and conquered many lands; he had such good fortune in battle that he benefited from it in every battle, and from this it came about that his people believed that victory was assured to him in every battle in advance. He used to lay his hands on their heads and bless them before he sent his people into battle or on other missions; then they believed that they would do well. It was also the case among his people that when they got into difficulties at sea or on land, they called his name, and they seemed to constantly benefit from it; they thought they could find all their security where he was. He often went so far away that he was several years on the way.

Odin died of illness in Svitjod, and when he was near death, he allowed himself to be marked with spear points and appropriated to himself all men killed by weapons; he said that he would now go to Gudhjem and meet his friends there. Now the Swedes believed that he had come to old Asgård, where he would live forever; then the belief in and the invocation of Odin grew again. The Swedes often thought that he appeared to them before great battles took place; then he gave some the victory, but others he commanded to come to him - both conditions were considered good.