2 Chronicles 7:15

Now mine eyes shall be open, and mine ears attent unto the prayer that is made in this place.

The promise was God's direct answer to Solomon's prayer at the dedication of the temple, given after seven days of dedication when the ceremonies were closed. Before that answer came, Solomon had assembled Israel together with people of many nations and taught that Israel's God is not shut up in a building like the gods of the heathen, but would meet His people by His Spirit when they gathered in the house dedicated to His worship, and he pleaded that God's eyes would be open toward the house night and day to hear the prayer made toward it. When Solomon finished praying, fire came down from heaven and consumed the burnt offering and the sacrifices, the glory of the Lord filled the house so that the priests could not enter, and the people bowed and worshiped.

In this verse God declares that He has heard Solomon's prayer and supplication and has hallowed the house to put His name there forever, with His eyes and His heart there perpetually, His eyes open and His ears attentive to the prayer made in that place which He chose and set apart for His name as a house of sacrifice. That attentive regard means His presence and favor are there for those who seek Him in the temple. His open eyes and attentive ears belong with His covenant call for His people to humble themselves, pray, seek Him, and turn from sin and wicked ways and wrongdoing, and when they do He hears, forgives their sin, heals their land, and shows mercy.

The hallowed building thus stood as a perpetual sign of His special favor to Israel as a peculiar people who alone among the nations preserved true worship by keeping His commandments. The promise was conditional on Solomon walking before God as David his father walked, in integrity of heart and uprightness, doing all that was commanded and keeping statutes and judgments, and then God would establish the throne of his kingdom upon Israel forever. That establishing of the throne continued the promise to David that he would not fail to have a man upon the throne of Israel. But if Solomon or his children, that is Israel, turned from following God, failed to keep His commandments and statutes, and served and worshiped other gods, God would cut off Israel from the land He had given them, cast the hallowed house out of His sight, and make Israel a proverb and byword among all peoples. The promises to hear and show mercy when His people humble themselves, pray, seek Him, and turn from wrongdoing were fulfilled during Hezekiah's reformation.