Albert Barnes Commentary 2 Samuel 7:27

"For thou, O Jehovah of hosts, the God of Israel, hast revealed to thy servant, saying, I will build thee a house: therefore hath thy servant found in his heart to pray this prayer unto thee." — 2 Samuel 7:27 (ASV)

Therefore hath thy servant found in his heart... - The promises of God are the true guide to the prayers of His people. We may dare to ask anything, however great it may be, which God has promised to give. In this and the two following verses, David expresses the same wonder at the riches of God’s grace, and the same expectation founded on that grace, which Paul does in passages such as Ephesians 1:5-7 and Ephesians 2:7.