Or HaChaim on Exodus 3:1/אור החיים על שמות ג׳:א׳

1 ומשה היה רועה…וינהג את הצאן, And Moses was a shepherd….and he led the sheep, etc. The Torah means that G'd had His hand in this, i.e. He caused the sheep to move in that direction. Alternatively, it means that Moses was in the habit of guiding his flocks as usual but the sheep walked to that mountain on that occasion for G'd wanted to speak to him there.