Exodus 2:11-13

And it came to pass in those days, when Moses was grown up, that he went out unto his brethren, and looked on their burdens: and he saw an Egyptian smiting a Hebrew, one of his brethren. And he looked this way and that way, and when he saw that there was no man, he smote the Egyptian, and hid him in the sand. And he went out the second day, and, behold, two men of the Hebrews were striving together: and he said to him that did the wrong, Wherefore smitest thou thy fellow?