The context of 2 Chronicles 7:14 goes all the way back to (and further than) the beginning of chapter 6. The account is the finishing and dedication of Solomon’s temple to God: and God’s statement to Solomon after the fact is this-
“Then the LORD appeared to Solomon at night and said to him: I have heard your prayer and have chosen this place for Myself as a temple of sacrifice.
If I close the sky so there is no rain, or if I command the grasshopper to consume the land, or if I send pestilence on My people, and My people who are called by My name humble themselves, pray and seek My face, and turn from their evil ways, then I will hear from heaven, forgive their sin, and heal their land.
My eyes will now be open and My ears attentive to prayer from this place. And I have now chosen and consecrated this temple so that My name may be there forever; My eyes and My heart will be there at all times.
As for you, if you walk before Me as your father David walked, doing everything I have commanded you, and if you keep My statutes and ordinances, I will establish your royal throne, as I promised your father David: You will never fail to have a man ruling in Israel.
However, if you turn away and abandon My statutes and My commands that I have set before you and if you go and serve other gods and worship them, then I will uproot Israel from the soil that I gave them, and this temple that I have sanctified for My name I will banish from My presence; I will make it an object of scorn and ridicule among all the peoples.
As for this temple, which was exalted, everyone who passes by will be appalled and will say: Why did the LORD do this to this land and this temple? Then they will say: Because they abandoned the LORD God of their ancestors who brought them out of the land of Egypt. They clung to other gods and worshiped and served them. Because of this, He brought all this ruin on them.” ~ 2 Chronicles 7:12-22 (HCSB)
Notice, how incredibly specific to the physical nation of Israel that this passage is. Also notice exactly what it is in verse 13 that God will “heal” their land from: drought, famine, and rampant, life threatening disease (that God Himself placed upon them for their sin).
When God moves to speaking of idolatry and the people utterly forsaking God’s ways – the punishment becomes far more severe; and “enduring,” if you will.
If the “spiritual” people (or self professed Christians) of the United States want to try and use this as a “banner text,” as it were, for their call to their fellow “believers” to pray for healing in America, there are a few things that should be pointed out:
1: Verse 14 is not a promise to the U.S. in particular or to “Christians” in general.
2: Even if it was a promise to Christians, America as a nation doesn’t belong to Christians. And a Christian, by definition, is already a repentant servant of God, so is practically incapable of following the “if” in verse 14 because they have, and are(and will be) already doing that.
3: Which leads us to a final point: you cannot repent for someone else’s sin(although you CAN suffer the consequences of it).