When you study Bible parallels, you have to understand that parallels are not only one means that God communicates to us in the scriptures, but that they are also an element of God's own name and nature. One of the names for the Holy Spirit (therefore of God Himself) is paraclete.
Paraclete not only means helper, but in fact the more literal meaning is one who is along side of (as in in walking parallel).
It is the Holy Spirit that reveals or opens up God's word to us. Speaking in parallels was the way that Jesus frequently spoke to the disciples. Jesus used parables which are parallels. Word pictures that told stories.
Some of the parallels in the Bible are obvious, such as Jesus' parables. Others are a bit hidden and require some digging and deep thinking (and most of all, guidance by the Holy Spirit).
One way of looking at the Jewish feasts is that they are parallels to other events. Paul himself said that the feasts were revelatory of Jesus. It's no wonder we see hope for the rapture in the feasts.
Once I saw the significance of parallels, I was able to see that the end-time church was the feet of the body of Christ... but, that's a different study.
YBIC
Bruce Baber