One may not build steps leading to ravines on the eve of the seventh [year] once the rains have stopped, because he is preparing them for the seventh [year]. But he may build during the seventh [year] once the rains have stopped, because he is preparing them for [the year] following the seventh. He may not support [the dam] with mortar, but he may make a [loose] partition. Any stone which one can stretch out his hand and take may be taken.