Right. For the ENTIRE service?
If you want to; I suppose.
Exodus 17:11
11 So it came about when Moses held his hand up, that Israel prevailed, and when he let his hand down, Amalek prevailed.
12 But Moses' hands were heavy. Then they took a stone and put it under him, and he sat on it; and Aaron and Hur supported his hands, one on one side and one on the other. Thus his hands were steady until the sun set.