You have no enemies, you say?
Alas, my friend, the boast is poor;
He, who has mingled in the fray
Of duty that the brave endure,
Must have made foes! If you have none,
Small is the work that you have done,
You’ve hit no traitor on the hip,
You’ve dashed no cup from perjured lip,
You’ve never turned the wrong to right,
You’ve been a coward in the fight.

Charles Mackay (1814-1889) Scottish poet, journalist, song writer

Poem (1884), “No Enemies”, Interludes and Undertones, Poem 121
    (Source)

The hitting on the hip is an allusion to Genesis 32:35.

A third-person version of the poem, titled "Not In It," was "Selected" as filler in The Medical and Surgical Reporter, Vol. 69, No. 19 (1893-11-04), uncredited:

He has no enemies, you say.
My friend, your boast is poor.
He who hath mingled in the fray
Of duty that the brave endure
Must have made foes.
If he has none,
Small is the work that he has done.
He has hit no fraud upon the hip;
He has shook no cup from perjured lip;
He has never turned the wrong to right;
He has been a coward in the fight.