Aww, and I like you. Why do you make me disagree so soon?
Jesus is not the author of confusion that exists on birth control in your own ranks. While most Catholics are bad on Birth Control there is no confusion at a theological level that it is wrong and the discussion on it is closed.
Except that the Roman Catholic writer John Noonan shows (rightly) than NFP would have been considered contraception by the early Fathers. And lets not do a "No True Scotsman" argument either -- "oh, if this Noonan fellow were a real Catholic he'd not have said that". Noonan wrote one of the best studies on the subject in English, but the facts are fairly simple: the early Church Fathers didn't use all sorts of distinctions to allow for a certain kind of birth control; if you went about your sex life in such a way as to increase the chances of avoiding procreation then you were using contraception. Of course, admittedly, this is very similar to divorce and remarriage, so at least Catholics are consistent.
First I would like to say that to use NFP without a grave reason is a grave/mortal sin.
NFP is not at the same level of using Artificial methods of Birth Control because the essence of the act of martial relations is not frustrated. It is not sinful for a married couple to have relations during times of the month when the women is less likely to become pregnant. It can be a mortal sin if the primary end of doing it is evil (selfishness, greed), not avoiding some evil (another child reducing the couple to abject poverty, government forced abortion, frail health of the women etc)
Divine revelation in Genesis 38 shows that God however harshly punishes any attempts to frustrate procreation by the spilling of seed, which in essence is what the use of condemns does. It appears to break the natural law, because the essence of the marital act is for the man to put seed in the women which can result in a pregnancy. The Catholic Church has always been consistent in its condemnation of the spilling of seed and of birth control. NFP is an allowance because the couple still copulates in a manner that still allows for pregnancy to happen and does not involve the loss of seed.
To my knowledge the Orthodox communions initially supported Paul VI Humane Vitae, but later in 2000 the Russian Synod allowed condoms. However, I would describe what I have observed from being an outsider that there is harsh tension in the Orthodox community over the sinfulness of the act and to what degree it is a sin. You have a local pastor in my area Father Josiah Trenham (Antiochian Orthodox St Andrews Riverside) who absolutely condemns any form of birth control, and to my knowledge I know Bishop Hilarion also is opposed to birth control. Everyone one else is either silent or invokes "economia".
My point when I said that our Lord Jesus Christ is not the author of this confusion was to point out that in the Catholic Church the Pope has ruled definitively on the matter that all forms of artificial contraception are evil. So it is safe to say the Catholic Church opposes artificial birth control, but you cannot say the Orthodox allows artificial birth control nor the Orthodox condemns artificial birth control because many voices without any absolute authority say different things.SN I would be interested in a citation from the book Noonan wrote were he concludes that periodic continence would have been condemned by all the early fathers. I am aware of some of the strict writings from the Fathers on matters like relations during Pregnancy and some of their very harsh comments about marriage but I would like to know more.