"how can one find out which where the truth is?"
The Ultimate Truth is not individualised, but in the end of the day we are all individuals! This means that we must follow the path that we are most comfortable and happy with - usually this is the belief system you are born into. All religions believe in a higher being - so start off with faith. Search. Find your goal. Then strive for it. Whether you call him Jahova, Allah or Krsna, He cannot ask more of you than to follow your God-given conscience when it comes to choosing a belief system.
"do these scriptures stand the Test of Time?"
You'll never know until the end of time! are you asking whether the scriptures remain untainted? The scriptures of Hindu, Muslim, Buddhist and Jewish religions actually do - only interpretations change vastly, hence sects e.g. Shaivism/Vaishnavism, Sufism etc. If you're asking which is the oldest religion - without question this is Sanatan Dharma (origin of modern-day Hinduism). But the age of this religion takes nothing away from the essence of other religions!
For thought - every single religion (that i know of) teaches Love (bhakti) for God. This is a nice place to start /ubbthreads/images/graemlins/smile.gif