Hi Anon
First of all, that is not a complete sentence.
Secondly, if the word "for" has been used with a meaning similar to "because", then the word "for" refers back to the previous sentence. This sort of use of the word "for" introduces a clause (not a phrase) that explains (gives a reason for) something that was stated in the previous clause or sentence. Look at this:
Great waves of coolness set him shivering, for he was shirtless as usual and wearing only his shorts and Keds.
In that sentence, the word "for" introduces the clause that provides explanatory information about why the coolness made him shiver. Unlike using the word "because, the sentence above cannot be inverted. In other words, you cannot start with the "for" clause:
For he was shirtless as usual and wearing only his shorts and Keds, great waves of coolness set him shivering.