Now therefore: These words introduce the conclusion to David’s prayer that began in verse 16.
May it please thee to bless the house of thy servant: May it please thee translates a Hebrew verb that means “to make a beginning.” It is often used as an expression of politeness or modesty. The parallel text in 2 Sam 7.29 has an imperative form of the verb that is literally “be pleased.” But here in 1 Chronicles the verb is better translated as a statement of fact by saying “it has pleased you” (New Living Translation) or “you have begun” (Braun). Numerous other versions follow this interpretation (so New Century Version, New American Standard Bible, New Jerusalem Bible, New American Bible, Bible en français courant, Nouvelle version Segond révisée, La Bible du Semeur).
That it may continue for ever before thee: For this clause and the previous one Parole de Vie provides a helpful model, saying “You have decided to bless my family, so that my descendants will always be kings in your presence.”
For what thou, O LORD, hast blessed is blessed for ever is literally “For you, Yahweh, have blessed and is blessed forever.” The meaning of this sentence is uncertain. Possible interpretations include the following:
• (1) The Hebrew participle translated is blessed may refer to Yahweh. New Revised Standard Version says “For you, O LORD, have blessed and are blessed forever” (similarly New Jewish Publication Society’s Tanakh, Traduction œcuménique de la Bible).
• (2) The participle may possibly refer to King David. Jewish Publication Version says “for Thou, O LORD, hast blessed, and so let [Thy servant] be blessed for ever.”
• (3) Perhaps the most likely interpretation is the one that takes the participle as referring to the house/descendants of David (so Good News Translation, New Revised Standard Version alternative translation, Bible en français courant, Biblia Dios Habla Hoy). This is the interpretation in King James Version, which places the words “it shall be” in italics to show that they are not written in the Hebrew: “for thou blessest, O LORD, and it shall be blessed for ever.” Moffatt is similar with “thou hast blessed it, O Eternal, and blessed it is for ever!”
Quoted with permission from Omanson, Roger L. and Ellington, John E. A Handbook on 1-2 Chronicles, Volume 1. (UBS Helps for Translators). Miami: UBS, 2014. For this and other handbooks for translators see here .