Law must be stable and it cannot stand still.

法律必须保持稳定但却不能一成不变。

youdao

The law must be stable, but can not be static.

法律必须稳定，却不能静止不变。

youdao

Law must be stable, and yet it cannot stand still.

法律应该是稳定的，但不能停止不前。----庞德。

youdao

For a liquid piston to work, its surface must be stable in the face of rapidly changing pressures.

ECONOMIST: An engine made of water

As with every game of rugby, it must be the stable platform on which England can build.

BBC: Injury-hit Wallabies look vulnerable

Man must be at the center of a universe on a stable planet, or else the core Catholic claim that the omnipotent ruler of the cosmos could satisfy his sense of justice only by sending his son here to be tortured to death begins to seem a little frayed.

NEWYORKER: Moon Man