At a time when the Church is perhaps at its most divided, living out unity has never been more important, Nicky Gumbel told a packed HTB conference at the Royal Albert Hall yesterday.

Labelling the conference a "visible sign of our invisible unity", Gumbel implored those gathered to focus on what brings Christians together, rather than what they disagree on. "There's something amazing about unity, something powerful about unity," he said, but it's not easy – humanity has been struggling with it since the beginning of time. "Adam and Eve fell out, Cain and Abel fell out ... unity is really hard."

Gumbel highlighted divisive issues that the Church in particular has been dealing with for years, including sexuality, women in leadership and baptism. It's easy to argue, to split, and to start new groups with those who agree with us, he said, but the beauty of Church is in its diversity. Paul urges the Ephesians to make every effort to remain united in difference, and we're all called to follow the example of Jesus in being humble and gentle, rather than arrogant.

"We're living in extraordinary times, in very exciting times, but also a time of great crisis," Gumbel said, speaking of both the world at large and the Church. "But in times of crisis we can split and run, or stand together. I believe this crisis is a massive opportunity for us as a Church to stand together, and fight together."

The key to this, Gumbel continued, is that unity is not doctrinal, but relational, modelled by the Trinity and all about Jesus. "What unites us is infinitely greater than what divides us," he said – and unity is not given to us as an optional thing. It was Jesus' last prayer before he was crucified, and it still is his prayer now: he is interceding for us and praying for our unity so that the world will believe.

"The message we have is that Jesus came to take away all our guilt, and we're now forgiven and free," he said. "What an amazing message – why are we fighting each other? It's a waste of time."

Unity, however, does not mean unanimity, or uniformity. The body of Christ is made up of different parts, and we need to embrace diversity within it – remaining united does not mean we lose the truth, Gumbel added.

Quoting John Stott, he said: "Love becomes weak if it's not strengthened by truth, and truth becomes hardened if not softened by love." In fact, Gumbel said, "The only way to get truth is through unity", because we need the whole body of Christ to represent God's heart for the world.

"We live in a divided world, which demands a united Church," he concluded, noting that division is the root of all the problems in the world. The good news is that we don't have to champion unity alone. "Unity comes from the Father who's key to the transformation of society," Gumbel said.

"We have a model of unity in the family of God ... we can have different views, but we're still one family."