1 Kings 2:4

4 and that the LORD may keep his promise to me: ‘If your descendants watch how they live, and if they walk faithfully before me with all their heart and soul, you will never fail to have a successor on the throne of Israel.’

Read 1 Kings 2:4 Using Other Translations

That the LORD may continue his word which he spake concerning me, saying, If thy children 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 on the throne of Israel.
that the LORD may establish his word that he spoke concerning me, saying, 'If your sons pay close attention to their way, to walk before me in faithfulness with all their heart and with all their soul, you shall not lack a man on the throne of Israel.'
If you do this, then the LORD will keep the promise he made to me. He told me, ‘If your descendants live as they should and follow me faithfully with all their heart and soul, one of them will always sit on the throne of Israel.’