my question to swamiji vivekanandar

Purity, patience, and perseverance are the three essentials to success, and above all, love. - Swami vivekananda .This principle i can't understand.my assumption is if we start think of sucess then definietly we have to face failure oneday.Or i can say we got sucess somebody going to get failure? so why we need to work towards sucess....i don't know why swamiji told like that?