Alternative solution:
Text[TraditionalForm[-1 + x^3 + y^3 == 22 z^3], BaseStyle -> {FontSize -> 24}]
or equivalently
Text[TraditionalForm[-1 + x^3 + y^3 == 22 z^3], BaseStyle -> {24}]
or
Text[TraditionalForm[-1 + x^3 + y^3 == 22 z^3], BaseStyle -> {Large}]
The advantage of this version is that it can be Printed and embedded inside any costructs like Row, Grid etc. without loosing the default appearance. Compare:

Of course one can achieve the same with Style:
Print@TraditionalForm[Style[-1 + x^3 + y^3 == 22 z^3, 24, FontFamily -> "Times"]]
Or even shorter using built-in named styles defined in the Core.nb stylesheet:
Print@TraditionalForm[Style[-1 + x^3 + y^3 == 22 z^3, "Graphics", 24]]
Print@TraditionalForm[Style[-1 + x^3 + y^3 == 22 z^3, "TR", 24]]
The style "Graphics" is the default style for displaying Graphics (see detailed explanations here) and the "TR" style just sets the base font to be "Times" and "Plain" (i.e. "Times Regular"):

-1+xpresented asx-1, or order and formatting. Hence both examples. – ciao May 07 '14 at 23:52