When did God reconcile the whole world to Himself?

God reconciled the whole world to Himself at the cross, when Christ hung on that cross. The work of the cross was the reconciling of the whole world, not a few. God was in Christ, not imputing their trespasses unto them, and committed unto us the word of reconciliation.

Les explains that reconciliation means taking two alienated parties and bringing them back into fellowship. The world is set aside from God, at odds with Him, enemies of God, yet God has done everything possible to reconcile them. Les directs us to verse 19, saying 'Ephesians 4,' where it declares God was in Christ reconciling not a few but the world. He clarifies that God was in Christ when He hung on that cross, reconciling the whole world unto Himself, not imputing their trespasses, and committing unto us the word of reconciliation, making us ambassadors. Les emphasizes that the work of the cross was the reconciling of the whole world. Hebrews says Christ tasted death for every man; He did not die for just the few believers but for the whole human race.

2 Corinthians 5:19

To wit, that God was in Christ, reconciling the world unto himself, not imputing their trespasses unto them; and hath committed unto us the word of reconciliation.

Did God reconcile only a few people or the whole world?

God reconciled the whole world, not merely a few people. Scripture says God was in Christ reconciling not a few but the world, and the cross was the reconciling of the whole world. Christ tasted death for every man, not only for believers, but for the whole human race.