The decision of the Anglican Primates last week to maintain the unity of the Anglican Communion was a "God moment", Justin Welby has said.

Last Wednesday, the Primates Meeting of Anglican archbishops reached a climactic moment in which the Communion had to decide whether to "walk together at a distance, or walk apart", the Archbishop wrote in a reflection on the meeting, published today.

"And what happened next went beyond everyone's expectations. It was Spirit-let. It was a 'God-moment'," he said.

The Primates agreed to "walk together", though the US Episcopal Church was suspended from full participation in the Anglican Communion for consecrating a gay bishops and approving gay marriage.

"As leaders of our Anglican Communion, and more importantly as Christians, we looked at each other across our deep and complex differences – and we recognised those we saw as those with whom we are called to journey in hope towards the truth and love of Jesus Christ," Welby said.

The Episcopal Church faces three years of penalties. Its bishops will "no longer represent us on ecumenical and interfaith bodies, should not be appointed or elected to an internal standing committee and... while participating in the internal bodies of the Anglican Communion, they will not take part in decision making on any issues pertaining to doctrine or polity," according to a statement from the Primates.

While celebrating the unity that was achieved, Welby admitted it remains fragile due to the complex nature of the Communion, which spans 165 countries. "It is always costly. It is always painful. It feels very fragile," he said.

"We must repent of wounding others who are especially vulnerable", the archbishop added, explicitly referring to LGBTI people. "Peronally the fact that people are persecuted for their sexuality is a constant source of deep sadness... I am deeply sorry for the pain that the church has caused LGBTI people in the past – and the present – and for the love that too often we have completely failed to show in many parts of the world, including England.

"The worst thing about that is that it causes people to doubt that they are loved by God."

Welby reiterated his desire for the Primates to "seek to make decisions bearing each other in mind, taking each other seriously, [and] loving one another despite deep differences of view".

"It's clear in Christian teaching that it's not for us to divide the body of Christ, which is the church," he said.

Welby added that the Primates had committed "in every part of the Communion" to evangelism. "To proclaiming the person and work of Jesus Christ – inviting all to embrace the beauty and joy of the Gospel and to proclaim that to everyone."