Shiva Purana
माध्यस्थेनापि निग्राह्यान्यो निगृह्णाति मार्गतः ॥ तस्याप्यवश्यं यत्किंचिन्नैर्घृण्यमनुवर्तते ॥ ३५ ॥
There is bound to be some ruthlessness in him who curbs or slays those worthy of it even by standing detached.
english translation
mAdhyasthenApi nigrAhyAnyo nigRhNAti mArgataH ॥ tasyApyavazyaM yatkiMcinnairghRNyamanuvartate ॥ 35 ॥
hk transliteration by Sanscript