It is a right translation. There are two aorist participles, "he who believed", "he who was baptised". Before I give you my opinion on this, I'd like to answer your second question, i.e., if we should only believe in Christ's baptism. Christ didn't have any need to be baptised, He fulfilled the custom showing that His way is not revolutionary and that we are in need of Baptism.
Why are we in need of Baptism? Isn't faith enough? The text is clear, that faith is not enough, "He that believeth and is baptized shall be saved", a rather accurate translation of the original. A more accurate one would be "he who believed and then was baptised, will be saved".
If one believes, why wouldn't he want to be baptised? If denial of Baptism reveals lack of faith, then we can see in this command a confirmation of faith: if you really believe, then prove it by your baptism. This is one sense, not the crucial, in my opinion.
We can understand a more important sense, if we think what Baptism is. Baptism is a mystery, the mystery of becoming dead for this world, sharing with the death of incarnated Christ. Anyone who participates in mysteries with faith, knows that mysteries can give a real, sensible, divine power or grace of the Spirit. Mysteries, for the true believers, are not 'theatrical' acts or legal customs; they transmit power. Besides this, mysteries introduce the believer to the whole life of the Church, showing thus that we are saved together with the other members of the Church and not alone.
This doesn't mean that if someone happened to be isolated in an island, would not be saved. Exceptions exist, but the Church protects us from transforming faith into an individualistic adventure that tends to egotism. This way we can understand the command of Mark 16.16 as meaning "get faith, enter the Church, share the Spirit of Christ by sharing His love and death, and you will be saved".
In regards to what has been stated above, firstly, it must be asked, is not belief irrational? Is it not but belief that gives to night's dream its quality of seeming real, that it appears real simply because we believe it to be real (until we awaken, that is)?
Secondly, by making belief the fundamental requirement of the system, does this not reinforce, or even force, either directly or indirectly, either openly or subliminally, all further apprehension to function through that same restriction, through that same belief, thus inhibiting any real subsequent quest for higher reason? Too, is this limitation not amplified even more so, by the very fact that belief can tolerate no doubt whatsoever, otherwise it would not be belief.
And, thirdly, is not such a system as this of rigid belief, which encourages feelings rather than reason, in direct contrast with the teachings of Plato and the quest for and of reason?
To end, let me ask, is it possible through believing to know thyself? Or is the opposite true that by believing knowing is inhibited?
It isn't proper to speak about a Christian "system". Even the requirement of faith is not absolute, as we can understand from the case of Thomas, who didn't believe in the resurrection of Christ until he had touched the wounds with his hands. On the other hand, in the case of Plato, although statements are examined with the help of reason, there are elements that obviously go beyond examination. Where or how in Plato is "proved" that there exists a Creator of the universe? Plato explicitly says in the 7th Epistle that there is a certain knowledge that can not be proved or just even exposed adequately.
Faith in the sense that is required in Christianity doesn't mean a blind devotion or fanatic adherence. Remember the invitation "taste and see that the Lord is good". Experience of truth is necessary, if one is not to be imprisoned in fanaticism. By mere belief one can not know oneself. This is also the reason of the commandment in discussion here, to ask for entrance in the life of the Church, where Christ is experienced in many ways including the senses and the reason.
In regards to what has been stated above, firstly, and again, it must be asked, is not belief irrational? Is it not but belief that gives to night's dream its quality of seeming real, that the dream appears real simply because we believe it to be real (until we awaken, that is)?
And secondly, and again, by overtly making belief the fundamental operational requirement of the religion, does this not reinforce, or even force, either directly or indirectly, either openly or subliminally, all further apprehension to function through that same restriction, through that same belief, thus inhibiting any real subsequent quest for higher reason? Too, is this limitation not amplified even more so, by the very fact that belief can tolerate no doubt whatsoever, otherwise it would not be belief. This would seem to be the case in regards to your reply above, for your reply is obviously structured through the rigid framework of specific belief. Though your answer may appear reasonable to a degree, it is still embedded in the specific belief.
Please excuse me for saying so, George, but coming from you, who has probably read more Plato than any of us, and whose expansive understanding of Plato we have all admired, it was a shock for me to read, “On the other hand, in the case of Plato, although statements are examined with the help of reason, there are elements that obviously go beyond examination. Where or how in Plato is "proved" that there exists a Creator of the universe?” I say it was a shock to read this, for in your defense of the primary position of irrational “belief” in Christianity, you have not only trivialized Plato but also minimized reason to the level of belief, or even less. I think that if this is the case with you, George, it would be reasonable to assume that it would be the case with any Christian, that the fundamental belief of the religion would always take precedence over Plato and reason, for such is the nature of belief.
From Proclus, “But of opinion (belief being fixed opinion) and phantsay and sense prevent us indeed from partaking of the presence of the God(s) and draw us down from Olympian goods to earth-born motions, for Titannically they divide the intellect that is in us, and divulse us from an establishment in wholes to the image of beings.”
Therein lies the crux of belief; it apprehends only in images, can never rise above the image, and thus draws us down into generation, into illusion! The position of belief is clearly shown in the line in the Republic, but why would I even have to mention that to you George. Belief is believing the image real, making the image real, for all believing is make-believing. If one apprehended that what is real, it would not be belief but knowing. But then you know all that, George.
If I understand your point, you make use of the word doxa, an opinion that is not certain/proved – it may be real/true or not. By the dream-example you may refer to the platonic cave where the inhabitants see only shadows of real things and they think that they see the whole of reality. Yet, even shadows bare some resemblance to truth (as a regular dream does too), and in Politeia, where Plato goes against mimesis, a painted bed still keeps some resemblance with a real bed.
Even in Plato a doxa or a mimesis are not completely isolated from truth, and they are dangerous precisely because their resemblance tends to fix in the minds of those having that belief/image the conviction that they see the complete truth. In Phaedrus Plato goes even against writing, saying that by having some truths written we believe we help our memory, although the contrary is rather true: we let the truth in the book and we stop living it in the present. Yet even Plato wrote, he even used poetical ways despite his suspicions against poets, he used myths, he used/introduced in philosophy the form of dialogue, which 'resembles' the living conversation, etc.
By doing all these Plato was inconsistent, or rather, did he try to make use of the real side of dreams? In Greek there is the word symbolon coming from syn (plus) and vallein (put something to its proper place). A symbol is a semi-reality that points to the truth asking from us to add what is missing in order to arrive to full truth. Plato's inconsistency is just this symbolical use of speech, myths, etc, i.e., shadows armed with the capacity of becoming points and invitations to light. Of course they keep also their dangerous shadowy nature.
Faith, in the sense of holding for something the irrational position that it is true, while we don't have any proof by experience or reason, is not the absolute start, or fundamental operational requirement of the religion. What is fundamental is what makes this faith possible.
An apostle may come to anyone and speak about the Christ, not anyone will believe. Why this person believed, and another person did not? The same for whole peoples: why Greeks became Christians, while Jews didn't? Why, in general, Christianity dominated the Western world and not the far eastern? The answer to this, is the foundation of religion, being the foundation of faith/belief.
What I tried to show in my first reply is that, in any case, Christianity is not satisfied with mere belief. Belief is not a satisfactory condition by itself. The aim is not to believe in God (even in the sense of trusting Him, not just believing that He exists); the aim is to know Him.
I don't see why you were shocked when you heard that in Plato there are elements that go beyond examination. This is simply what happens, and not only with Plato, but even with the cold professor Aristotle, who says that some things can not be proved, their knowledge is attained by other ways. St. Macarius the Great writes that “All think they are Christians, for a proclamation of their faith in Christ, or even for some virtues, yet true Christians are few, they who are rich in the Holy Spirit, who enjoy the numerous pleasures of Grace, who delight in the heavenly desire of the Spirit, who are adorned in their soul with several heavenly clothes of Gifts; they who have Christianity not in confession and faith in words, but in the power and energy of the Spirit, they who touch unceasingly in their mind with the hands of the soul the heavenly gold, the knowledge and narration of the mysteries of the Spirit, only them are true Christians.”
This teaching, common place at least in Orthodox Christianity, reveals that 'faith in words', religion as holding a verbal/imaginary belief, is far from being enough. St. Macarius says that this is a false Christianity, but I wouldn’t go that far, keeping Plato's way, the symbolical value, regarding it as an uncertain condition, between falsehood and truth, a shadow that may or may not help one arrive to truth.