What is the Orthodox Church?
The Orthodox Church, put simply, is the Church of Christ. It claims direct lineage from Christ's Holy Apostles. It is attested to in Scripture; it is the "Church" of Matthew 16: 18, and the "Pillar and Ground of Truth" of 1 Timothy 3: 15.
"Extra ecclesiam nulla salus",
according to Saint Cyprian of Carthage: Outside the Church, no salvation.
We, as Orthodox, must accept this simple fact, and so we do 
not
waver from the Apostolic faith. The Church has four distinguishing
marks: One, for the Mystical unity of the Churches of God, Holy, for the
teachings of its Divine founder, Catholic, universal in its salvific
message, and Apostolic, proclaiming the faith of the Apostles, through
their descendants. Through two thousand years of suffering and victory,
the Orthodox Church moves slowly along today, joyfully and patiently
awaiting Christ, as it has for two thousand years.
Doesn't the Roman Catholic Church teach the same thing?
In a real sense, yes. The Roman Church was once the "first among equals" in the Holy Church. However, from the seventh century on, the See at Rome began to adapt the unchanging faith to the conditions of the times. When the change had become so great it was no longer Orthodox, the Pope of Rome departed from the Orthodox faith. But the question remains: does it still contain the same faith?
In the 7th century, the Church
of Spain made the fatal decision to add to the universal creed of the Church.
Through a series of political intrigues that really don't merit discussion,
the altered creed was sung in the Church of old Rome a scant three
hundred years later. Other changes would follow: the Pope of Rome would
attempt to exert universal control over the Eastern Church. The Western
Church would begin 
mother.
Slowly the Roman Catholic Church would begin to attempt to crystallize
the mysteries of God into a system that could only be called "human" in
origin. The only response to come would be the Protestant reformation,
deleting not only what was bad in Roman Catholicism, but what was
good.
The only answer I can give is to look at the faith of the Roman Church. Is it the faith of the undivided Church? Did the undivided Church teach that the bishop of Rome could make judgments to be believed with "divine and catholic faith"? The answer, put simply, is no. Does it hold to the idea of the head of the church being the local bishop, as the early Church did? No. Did it not add to the creed, ordered to be unchanged at the council of Chalcedon? It did. "By their fruits you shall know them," says our Lord.
Why not just believe in the Bible?
The Bible is the record of God's revelation to us, and Orthodoxy venerates it highly. That having been said, the Bible does not, in and of itself, contain sufficient information to form a cohesive system in Christ's plan. One need only look at the hundreds of different groups, with differing beliefs, all "based on the Bible." It didn't work centuries ago. It won't work now.
Many competent Orthodox Fathers
also point out the fact that the Bible is not something that can be really
believed
in in the normal sense. The purpose of the Bible 
is
to illumine the Christian soul. Outside of this, it can be used only
for destruction. Just as many useful things we use throughout the
day are poison if we eat them, the Bible is not meant to be read and misread,
or it will destroy us..
Isn't faith in Jesus enough?
"Nay, even the demons believe, and tremble," says the Apostle James.
If that's all you know, God will judge you. It's not my position to say. But now that you have read these lines, it would be simple and sheer folly to ignore even the possibility that you might be wrong. "Faith without works is dead," according to the Apostle James. What risk do you wish to take with your soul?
Believing in Jesus is good. But acting on your belief, living by your belief is far better. You say you believe in Jesus. Then why is there a problem with joining the Church He founded?
What, then, can one do?
There is but a simple solution. All men live their lives in a constant journey of faith; their awareness of this fact varies. If you know you are genuinely searching for truth, look up one of the jurisdictions on this page. Pray for guidance, and find the nearest Orthodox priest. It may be the most important move you could ever make-and one of the most difficult. But what if it's the only move you have left?
Don't "leave it up to God" when He asks you to make a commitment to Him. If God were your spouse, would you leave him (or her) hanging like that? Well, God is more than your spouse, for God is the Father and Creator of all; perhaps going to a priest would be a worthy consideration.
All Icons are images from Holy Transfiguration Monastery.