When Jesus taught his followers to pray, did he teach anything about the position of the body.... What is best?
Is it better to be sitting or kneeling? Head on the floor, bowed, looking up?
Should you put your palms together, up in the air, or another posture?
Is there a significance or purpose in the posture? Can a wrong or disrespectful position affect the quality of the prayer?
What do you recommend?
The standard prayer position in Jesus' time was what is called the orans posture. Where one is standing with hands turned up and raised. This is still the posture traditional Christian clergy take during the traditional Liturgy. It's what St. Paul referred to when he writes,
"I desire then that in every place the men should pray, lifting holy hands without anger or quarreling;" - 1 Timothy 2:8
Other postures of prayer include prostration (laying face downward on the ground) and genuflection (aka kneeling). Holding the hands together, clasping them, bowing the head, closing one's eyes or keeping them open, etc are all other common prayer postures.
In the context of organized Christian worship, aka the Liturgy. Depending on what kind of church and how their liturgy looks, generally we do things in unison.
When it comes to personal devotions or private prayer, there's no right or wrong way. I will, when I spend time in prayer, cross myself regularly, open my hands up in the orans position, sometimes when my knees aren't hurting too much I'll kneels. I rarely prostrate myself during prayer these days, simply because it's getting harder to for my body to do things like that these days.
The only thing that could "affect the quality of the prayer" is the disposition of the heart, in which case it's not about the quality of the prayer, but rather about the prayer-er. God hears even the unspoken groanings of the heart (Romans 8:26), so what position you're in doesn't matter. What matters is the state of our heart when we enter into prayer, we should enter into prayer with humility.
I often enter prayer confessing my sin and praying for God's mercy, usually along with the Jesus Prayer while making the sign of the cross,
"
Lord Jesus Christ, Son of God, have mercy on me, a sinner."
When I am particularly concerned with something I might say the same, and cross myself in different ways. In some of the earliest writings about the Christian practice of crossing ourselves, one would make the sign of the cross between the eyes, on the lips, and on the heart--as though to pray that our minds, our words, and our heart be held captive by Christ. And so I'll occasionally do the same,
"
Lord have mercy on me, a sinner."
I often also pray the Prayer of St. Francis, either in part or in full,
"
Lord, make me an instrument of your peace.
Where there is hatred, let me sow love;
where there is injury, pardon;
where there is doubt, faith;
where there is despair, hope;
where there is darkness, light;
and where there is sadness, joy.
O Divine Master, grant that I may not so much seek
to be consoled as to console;
to be understood as to understand;
to be loved as to love.
For it is in giving that we receive;
it is in pardoning that we are pardoned;
and it is in dying that we are born to eternal life. Amen."
I will prayer for friends and family, for my neighbors, and anything else that is on my mind.
And I also will frequently pray the Gloria Patri, especially as a way to close my prayer time,
"
Glory to the Father, and to the Son, and to the Holy Spirit, as it was in the beginning, is now, and ever shall be. Amen."
I don't have a rigorous prayer routine, there are many prayer resources out there, like the Daily Office, the Book of Common Prayer, etc. I've thought about having a more disciplined prayer routine, but since it's just me, I tend to just pray. The above is a fairly loose and broad example of how I pray. And thus it is nothing more than that: It's just how I pray.
-CryptoLutheran