‘No parliament can under any circumstances be an arena of struggle for reforms for the betterment of the conditions of the working class… the only purpose can be that of utilising bourgeois state institutions for their own destruction’

These words are not contained in Lenin's book What Is To Be Done? They appear to have been copy and pasted from David Shub's Lenin biography and it seems it the sentences were mistranslated or garbled version of a resolution on parliamentarism passed by the Second Congress of the Communist International written by Bukharin which reads:

"At present, parliament, for communists, can in no way become the arena for the struggle for reforms, for the amelioration of the position of the working class, as was the case at certain times in the previous period. ... Therefore there can only be a question of utilising the bourgeois state institutions for the purpose of their destruction."