1 Samuel 15:9

But Saul and the people spared Agag and the best of the sheep and of the oxen and of the fatlings, those of the second brood, commonly considered the best, and the lambs, and all that was good, and would not utterly destroy them, taking them, instead, as their booty; but everything that was vile and refuse, which had little or no value, that they destroyed utterly. Partial obedience is equivalent to total disobedience, and such a course of action inevitably brings upon the transgressors God's punishment.