Sentence:  `` The faithful should be excited to the reading of the Holy Scriptures : For these <WSD>are</WSD> the most abundant sources which ought to be left open to everyone , to draw from them purity of morals and of doctrine , to eradicate errors which are so widely disseminated in these corrupt times '' . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)