'Unable' in the Bible

The priests were unable to enter the Lord's temple because the Lord's splendor filled the Lord's temple.

Their descendants remained in the land (the Israelites were unable to wipe them out). Solomon conscripted them for his work crews and they continue in that role to this very day.

Eliezer son of Dodavahu from Mareshah prophesied against Jehoshaphat, "Because you made an alliance with Ahaziah, the Lord will shatter what you have made." The ships were wrecked and unable to go to sea.

They were unable to observe it at the regular time because not enough priests had consecrated themselves and the people had not assembled in Jerusalem.