Matthew 17:1-8; Mark 9:2-10- Who or what did the disciples see?
We know that Elijah was taken into glory without experiencing death (2 Kings 2:11). We also know that the body of Moses taken by the archangel Michael (see Jude 9). Apparently Moses was then given immortality. Therefore, the disciples saw, just as the Scriptures say, Moses and Elijah.
Luke 23:43- What did Jesus mean?
There are two possibilities (and both may be true). First, that Jesus actually said, 'I say unto you today, with me you will be in Paradise.' In other words, He was saying, 'I'm telling right now (today) that you will (one day) be with me in Paradise.' Second, that because Paradise is within the timelessness of God, Jesus can pronounce a future event as though it had already occurred. A lot of prophecy is written this way. This is because once a person enters the timeless realm of the Spirit, he is then present at all points of linear time. This explains how Paul can say that Jesus 'is before all things' (Colossians 1:17). Why didn't he say that Jesus 'was before all things'? It is because ever since the ascension, Jesus has been present simultaneously in all points of time. He is at once the beginning and the end.
I Peter 3:18-22; 4:6- What was Peter speaking of?
Please see our response to the question posted on 3/3/2009 titled 'Who were the spirits in prison?'
Revelation 6:9-11: Who are these martyrs? Souls/Spirits of dead believers?
This passage refers to the believers who have been or will be martyred for their faith in Jesus. They are mentioned again in Revelation 14:13; 18:20, 24; and 20:4. The phrase 'souls under the altar' simply means people who have experienced a sacrificial death for their faith.