Iwashimizu Hachiman-gu is a holy place where religious souls gather to pray. You can do the same, or simply observe others in worship.
You'll have sightseeing choices galore when spending time in Yawata. Iwashimizu Hachiman-gu is a great place to kick off here, but there are lots of other interesting attractions to discover. Kyoto Racecourse, Hirakata Park, and Kuzuha Mall are close to the sacred place and will fill in your day nicely.