Twitter is not the best place to have a row, the Archbishop of Canterbury has said. In fact, in some ways it is one of the worst because it does not allow visible facial expressions and body language.

Justin Welby says in new blog posted today that if you want to tell someone off, the answer is not to tweet angrily to them but instead put an arm around their shoulder and show them your tears.

Electronic media has no "volume control", he warns. "Electronic media breaks through locked doors, and pierces people painfully."

The blog, titled: "On tweeting and touching", comes on the heels of a sermon when the Archbishop told vicars to stop filling sermons with "claptrap" platitudes about being "a bit nicer."

The Archbishop is a controlled and expert user of Twitter, where he has nearly 80,000 followers, but has been known to vent strong feelings on the telephone, another medium where a person's expression cannot be seen by the speaker. His predecessor Rowan Williams was not on Twitter.

In the blog, he says: "I will remember for a long time a letter I received in the last few years from someone who'd gone through a particularly difficult conflict in the church. It was full of what can only described as deep trauma and sorrow. It had been deeply damaging."

There were lots of reasons for this, he says, but one that had been on his mind recently had to do with electronic media such as Twitter and blogs.

"The trouble is that subtleties, tone and access all get muddled up," he continues. "The subtleties we lose when we communicate electronically have to do with expression, with touch, with the face-to-face aspect of relationship.

"Social media does not show tears in the eye, a hand on the arm when saying something painful, body language that speaks of inner turmoil, deep distress – even gentle respect. It is simply there – usually forever."

This was not the biblical way to disagree. The Bible demands a more personal way of relating, he says. "It starts with personal meetings, and goes on to wider disciplines. It sets something in motion; a new stage of relationship. Print and electronic media is often just static and there, often indelibly, locking us into a permanent present tense that hinders healing."

For disputes within church communities, Jesus in Matthew's Gospel makes it clear that personal interaction is essential. "Yet all of us feel that when someone has done something wrong, we should all say so! Electronic media breaks through locked doors, and pierces people painfully."

In a semantic echo of St Paul's writings on charity, the Archbishop says: "Love often says don't tweet. Love often says don't write. Love often says if you must rebuke, then do so in person and with touch – with an arm around the shoulder and tears in your eyes that can be seen by the person being rebuked."