Anna,
what you have said is true, and it would make you wonder about a book that believers call the Word of God,and be Good News for all people, yet which seems not to in any way to include the entire world.
I don't know if this will help you, but here as briefly as I can make it, is a summary of the Bible and why it was written in the form it is written.
The Bible, whilst it is definitely a book of spiritual teaching, is also a history book.. not of one particular nation, but of God's dealing with humans from the beginning of the created world. It is primarily a book about God relating to those He has created and our response to that relationship.
The Bible teaches that at creation, man (here it means humankind.. men and women), were created in the image of God and with the awesome ability to walk and talk and know God intimately. In every human being, there is a spiritual awareness which craves that intimacy with the creator God and is the reason why you say in your post that "I do find myself reading the thoughts of people of just about every religion. Since I have not yet found spiritual answers in any given religion that suit me, I tend to keep looking.
When man chose to do his own thing and disobey God, not only did he bring death (spiritual death as well as physical death) onto himself, he also more significantly lost that relationship, that intimacy with God. The Bible teaches that man could do absolutely nothing to restore it.. even the very best deeds he did, even if he was as good a human as he could be, it was not enough. What had happened inside him.. the spiritual death that occured, would keep him forever without that relationship with God that He was created to have. He became embarrassed and hid from God. The covering he made for himself could do nothing to solve the spiritual problem that existed.. a total breakdown of the relationship between God and Man.
From the moment of the fall, God provided a sacrifice or a covering which would enable Man to be in fellowship with Him again. This was to be the pattern of God dealing with man and restoring relationship.. God did it all. The Bible speaks of God restoring Adam and Eve to Himself by providing a "covering" for their shame and embarrassment. But it was still not enough. In those same verses, we read for the first time of God's promise of a final solution.. the Messiah, the Christ who would take away forever, the spiritual separation of man and God and restore what Man had at his creation.
The Bible then teaches two things
1. One nation (Israel) was chosen to be God's special people and to be blessed, so that they would be a blessing to all nations of the world, in being God's way of bringing salvation to all humans
2. A spiritual principles.. obedience leads to life and disobedience leads to death. Yet always, judgement, no matter how it was delivered, had as it's primary reason, that humans would return to God.
Most of the Old Testament then discusses how God deals with Israel, staying true to these two principles. and always threading through it, is the promise of the coming of the Messiah, who would be the final solution. The sacrificial system as described in the Old Testament, the demands of the Law.. all were but a picture to describe the coming of the Messiah.
Then the Bible says, the event that all history was waiting for happened. It has been described as HIS STORY ... Galations says "at just the right time God sent his son". If the Old Testament talked of the promise of the coming of God's solution to man's eternal separation from Him, The Gospel stories tell of it's actually happening and the New Testament speaks of the effect it had, not only on Israel, and the countries surrounding the middle east.. but onwards into the entire known world at the time.
The Christians were persecuted during the reign of the roman emperors and they spread out.. and every where they went they shared the good news that in Jesus Christ alone, that spiritual longing that all humans are born with, could be resolved. Because of his death and resurrection, man could again be restored to relationship with God, and the penalty for sin, eternal death and separation from God, was paid for by God Himself.
The bible says "For God so loved the world (and in this respect, he means, every man, woman and child ever born or ever to be born) that He gave His only son, that whoever believes in Him, would not perish, but have eternal life".
Jesus told His Disciples to "Go into All the World and tell everyone everywhere the good news".
Only a few nations might be specifically mentioned in the Bible, but the effect of God's dealing with those few nations, was not just to be felt in their part of the world, but the entire world "until he comes again" as preacherintraining reminded us, in his post.
I've left lots out, but I hope this helps you understand or at least grasp a little of the message of the Bible. It truly is meant for all nations and all peoples.
Anna, I hope it helps a bit and please, ask as many questions as you like. We are truly here to help answer any questions we can in a way that hopefully will help you find the answers you are so obviously seeking.
Hopefully we'll keep talking
Carol