Why are we reconciled to God and made joint heirs?

Les explains that under Paul's gospel, the minute a person believes, they immediately experience the fullness of atonement. He breaks the word into three syllables—at-one-ment—and calls that the best definition he can find: as soon as we believe, we are at-one-ment with God Himself. He then says we have reconciliation, another big word; we are reconciled to God, in full fellowship with Him, we are His, and we are a joint heir. All these good things have happened simply because we believe the gospel. He adds that he is not taking away other ramifications of the Christian experience, and he notes his reluctance to emphasize local churches because many can mislead and not feed people from the Word, though he does not say all do.