Ilfa and Rabbi Yochanan were students stricken with poverty who decided to leave their studies to make money. Their decision was based on the statement in the Bible, Deuteronomy 15:4, "There shall be no poor among you." Rabbi Yochanan heard two angels talking, saying that they should destroy them. One of the angels said that the men shouldn't be destroyed, because one of them has 'time on his side' meaning that in his life he will achieve greatness. Rabbi Yochanan decided to return to his studies after hearing this.
Rabbi Yochanan had to sell property slowly and was able to survive this way. In his old age, he told Rabbi Chiya bar Abba the situation, and said that he wasn't upset that he had no money, because that is only a material thing created by G-d.
Ultimately Rabbi Yochanan was elected 'nasi,' leader, whereas Ilfa was not, despite the fact that Ilfa had continued his learning while engaged in commerce.
- adapted from Artscroll Siddur