Will, Shall

In formal writing, the future tense requires shall for the first person, will for the second and third. The formula to express the speaker's belief regarding a future action or state is I shall. I will expresses determination or consent. A swimmer in distress cries "I shall drown; no one will save me!" A suicide puts it the other way: "I will drown; no one shall save me!"

William Strunk, Jr. and E.B. White, The Elements of Style