With the first person
The modal auxiliary verb shall is used with first person pronouns to express the strong possibility or near certainty of an action which is to take place in the near future.
- I shall leave for Chicago tomorrow.
- We shall discuss the matter with the chairman.
- I shall be thirty one next Tuesday.
With the second and third person pronouns
Shall can be used with second and third person pronouns to express a command.
- You shall not lie. (= You are commanded not to lie.)
- She shall obey my orders. (= She is commanded to obey my orders.)
- He shall go at once. (= He is commanded to go at once.)
Shall is sometimes used with second and third person pronouns to express a threat.
- You shall regret this.
- They shall pay dearly.
Shall may also express determination.
You shall apologize. (= You will be obliged to apologize.)
Will
With first person pronouns
With first person pronouns will expresses ideas such as determination, promise, threat or willingness.
- I will go there, whatever happens. (Determination)
- We will not let you go. (Determination)
- I will try to get him a good job. (Promise)
- I will teach you a lesson. (Threat)
- All right, I will come with you. (Willingness)
With second and third person pronouns
When used with second and third person pronouns will expresses simple futurity.
- The train will leave at 9.40 pm.
- He will be back in a day or two.
Distinctions between shall and will
The distinctions between shall and will are fast disappearing. Shall is now hardly used with second and third person pronouns. In the first person, however, shall is still being used to indicate simple future.