in one's power

Well, if this is so, one has no choice but to do all in one’s power to change that fate, and at no matter what risk—eviction, imprisonment, torture, death.

But, to be sure, they laugh if one gives to a dog's faithful devotion the name of friendship, if with thankful recognition one strives to repay as far as lies in one's power the humble comrade whom they call but a soulless animal, whose fine, sensitive thought they call instinct, and for whose honest, noble soul they deny all right to live any longer than his faithful dog-heart beats.

Overmaster, ō-vėr-mas′tėr, v.t. to subdue, to govern: to get and keep in one's power.

Mercy, mėr′si, n. tenderness and forbearance shown in sparing an offender in one's power: a forgiving disposition: clemency: an act of mercy: an undeserved blessing: compassion or benevolence.—adjs.

And, as they said, many other things may be classed as good if it is in one's power to use them either well or ill.