Explain the reasons for Stalin's triumph to leader of the USSR by 1928? Can you help to explain a quote to me?

Stalin was General Secretary and used his power to appoint officials,this gave him an advantage when he wanted to get rid of his enemies. I think the quote comes from this period because he didn't speak much in meetings. He would sit and listen and remember. He never had the charisma or the intellect of Trotsky or Bukharin but while they were thinking about the betterment of the Party he was planning the betterment of Stalin.