'Take Heed' in the Bible

that Jehovah may confirm his word which he spoke concerning me, saying, If thy sons take heed to their way, to walk before me in truth with all their heart and with all their soul, there shall not fail thee, said he, a man upon the throne of Israel.

And now, Jehovah, God of Israel, keep with thy servant David my father that which thou hast promised him, saying, There shall not fail thee a man in my sight to sit on the throne of Israel, if only thy sons take heed to their way, to walk before me as thou hast walked before me.