What is unusual about the way dimmesdale walks as he goes toward the meeting house

When Dimmesdale walked in the procession in the Scarlet Letter in Chapter 22, there was no feebleness of step as at other times; his frame was not bent, nor did his hand rest ominously upon his heart. Yet, if the clergyman were rightly viewed, his strength seemed not of the body. It might be spiritual and imparted to him by angelical ministrations