Tener de is used in threats—
Tengo de llevarlo ante el tribunal: I shall take him before the court.
"Tener que hacer, que escribir, que comer" and similar expressions translate also "to have something to do, to write, to eat," as—
Hoy tengo que hacer: To-day I have something to do, I am busy.
Tengo mucho que hacer: I have much to do.
Tenemos que comer por todo el día: We have something to eat which will suffice for the whole day.
Haber is used as a principal verb instead of Tener in—
Haber menester de algo: To need something.
He aquí el muchacho, etc.[156]: Here is the boy (behold the boy here, etc.).
Héme aquí or héteme[157] aquí, etc.: Here I am (behold me here, etc.).