Jesus took three parts of Isaiah’s kingdom message and set about implementing them. Release for captive Israel; the defeat of evil; and the return of YHWH to Zion.
Rather think of it like this. Jesus was the medical genius who discovered penicillin, we are doctors, ourselves being cured by the medicine, now applying it to those who need it. Jesus is the musical genius who wrote the greatest oratorio of all time, we are the musicians, captivated by his composition ourselves, who now perform it before a world full of muzak and cacophony.
There is one important spin-off of this. Along the unbiblical view of the Kingdom that sees it as the escape from the created order, rather than the redemption of it, there is a view of prayer that sees it as essentially the activity of the mind, the heart, or the soul, leaving the body untouched and irrelevant. This view has a certain strength: it will never fall into ritualism or magic, or into thinking that we can put on a pretty little outward show which God will then politely applaud.
But that’s actually about all that can be said for it. They kingdom come on earth as it is in heaven; and we who pray that prayer are ourselves bits of earth, lumps of clay. If we really want God’s kingdom to come on earth, we should of course expect that the earth in question will include this earth, this clay, this present physical body. That means, of course, holiness. It means, of course, sacraments, it means the physical act of prayer.
Sadly for those who like everything tidy there are no rules at this point…
The ideal posture they would tell us is relaxed but not slumped; poised but not tense; alert but not fidgety; above all, humble but happy in the presence of the Creator whom you are learning to call ‘Father’. Find the posture that does all that for you, find the gestures that express and symbolise the life and love of Jesus for youl and you will be teaching your body to pray – which to the surprise of many modern persons, is no bad way to teach your mind, heart and soul to pray as well.