וַיָּבֹא֙ הַמֶּ֣לֶךְ דָּוִ֔יד וַיֵּ֖שֶׁב לִפְנֵ֣י יְהוָ֑ה וַיֹּ֗אמֶר מִֽי־אֲנִ֞י יְהוָ֤ה אֱלֹהִים֙ וּמִ֣י בֵיתִ֔י כִּ֥י הֲבִיאֹתַ֖נִי עַד־הֲלֹֽם׃
Then David the king went in, and sat before the LORD; and he said: ‘Who am I, O LORD God, and what is my house, that Thou hast brought me thus far?
Rashi
therefore, Your servant has found [occasion] to pray before You i.e., If You Yourself had not promised me to bring upon my seed these favors, it would not enter my mind to make supplication, for who am I that You have brought even this far, but since You said for Your sake to bring me all these favors, I therefore pray that You cause Your words to be realized.