'Take Heed' in the Bible

to the end that Yahweh may establish his word which he spake concerning me, saying, If thy sons will take heed to their way, by walking before me, in truth, with all their heart, and with all their soul, (then, said he) there shall not be cut off to thee a man, from off the throne of Israel.

Now, therefore, O Yahweh, God of Israel, keep thou for thy servant David my father, that which thou didst promise him, saying, There shall not be cut off to thee a man from before me, to sit upon the throne of Israel, - if only, thy sons take heed to their way, by walking before me, as thou hast walked before me.