King David stands in absolute awe before the divine promise regarding the future of his dynasty. He recognizes the vast gap between his mortal standing and the supreme grace bestowed upon him. Throughout his life, David views himself simply as a servant whose main purpose is to fulfill the word of God, rather than someone chasing personal greatness [ביאור שטיינזלץ]. He understands that this profound news stems completely from God's absolute will, rather than from any personal merit he has accumulated.
The primary approach among commentators is that David openly acknowledges his own unworthiness for such immense greatness, realizing it was given to him solely by God's decree. Some explain that this reflects the fulfillment of the original promise God made to the prophet Samuel to anoint David as king [רש״י, רד״ק]. The dual emphasis on God's word and heart serves to firmly reinforce that this is entirely an expression of His will [רד״ק]. Another perspective suggests that David momentarily wondered if this kindness was a reward for his noble intention to build the Temple. However, he quickly realized that his human intentions could never equal such a massive display of divine grace. He concludes that these events flow exclusively from God's wisdom and will, since divine matters are not driven by external factors [אברבנאל].
A significant question arises regarding why God needed to inform David about the future at all. God could have simply carried out His kind plans without giving any prior notice. One approach views this as a double kindness. David is amazed that God did not stop at the act of grace itself, but went further by telling him in advance, almost as if it were a reward for his deeds [מצודת דוד]. Another view maintains that the act of informing him, just like the grace itself, flows purely from God's free will and wisdom, without any obligation [אברבנאל].
A much wider perspective explains the purpose of this prophetic notification. Generally, a prophet is sent to warn of danger, inspire repentance, or offer guidance, rather than to deliver good news to a private individual. Because David received this message through a prophet, he grasps that it is not merely a personal update. Instead, it represents a comprehensive historical movement that impacts the perfection of the entire nation. The advance notice is meant to reveal God's plan and guidance from the very beginning to the end of days. Much like prophecies concerning the messianic era and the ultimate repair of the world, this message uncovers God's hidden will as it guides the course of history [מלבי״ם].