Section 16. The clerk of a division of the district court department before entering upon the performance of his official duties, and thereafter, at intervals of not more than one year, so long as he continues to hold such office, shall give to the commonwealth a bond, conditioned to perform faithfully his official duties, with a surety company authorized to transact business in the commonwealth, as surety, in a sum approved by the chief justice of the district court department, but in no event less than five thousand dollars. Failure to give such bond shall be sufficient cause for his removal.