Addressing the Third Lausanne Congress on world evangelisation today, the renowned theologian said Christians had lost their integrity and succumbed to the idolatry of power and pride, popularity and success, and wealth and greed.
"What do you think is the greatest obstacle to God's desire for the evangelisation of the world? It's not other religions. It's not persecution. It's not resistant cultures.
"The greatest problem for God in his redemptive mission for the world is his own people.
"What hurts God the most is not just the sin of the world but the failure, the disobedience and the rebellion of those whom God has redeemed and called to be his people."
Such idolatry, he said, had become the "biggest threat" to world mission. In some parts of the evangelical community, he said an "obsession" with statistics and outcomes was leading to "wild claims and unsubstantiated numbers", as well "untrue reports, manipulation and collusion in falsehood".
"We cannot build the Kingdom of God on foundations of dishonesty, telling lies about our success or accepting what we know to be questionable statistics in order to access grants and funding for our projects. [That] is nothing short of bowing down to the idolatry of manipulated success."
While it was right to affirm what the Bible had to say about God's blessing and the power of the Holy Spirit, Wright said some preachers were distorting the Bible "to appeal to human greed" whilst making no mention of what the Bible had to say about suffering and the call upon every believer to take up their cross.
Such prosperity gospel preachers, he said, are succeeding "only in enriching themselves" in a lifestyle that is contrary to the teaching and example of Christ.
Also marked out for criticism were the false prophets and "super apostles" who, although popular with thousands of Christians, are "unconcerned for the weak and the poor", "show none of the marks of the apostle", and bear "no resemblance to the crucified Christ".
To even be concerned about status, office or power in the Christian church and in Christian work, he said, was "sheer disobedience to Christ [which] destroys the very thing that we are seeking to accomplish".
He warned that the level of idolatry among Christians was such that they had become a "scandal" and a "stumbling block" to the mission of God, and could no longer speak out credibly against the errors of the world.
"The tragedy is that so many Christian leaders, including mission leaders, fail these tests [of power, popularity and wealth] at precisely the point Jesus overcame them. They simply can't resist the temptation of elevating status [and] of manipulating success," he said.
"The whole church pays the cost of their failure in the lost integrity and credibility. And so when we even dare to point the finger of criticism at the sin of the world we are told bluntly and rightly 'clean up your own backyard'."
Wright said that reformation had again become the "desperate need of the day", starting with evangelicals.
He urged Christians to repent and stop ignoring their own failings as he called for a "radical return" to Jesus and Scripture, as well as Bible-based preaching.
"Before we go out to the world we must come back to the Lord. If we want to change the world we must first change our own hearts and ways. As we take the words of the Gospel to the world we must also take with us words of confession to God, and before we get off our seats to seek the lost we need to get on our knees to seek the Lord."
He concluded with three words for the church today – humility, integrity and simplicity - or H.I.S.
"Are we 'his' people? Let us then be what we are for God's sake, for our mission's sake and for the world's sake."