4.1 What is Hell?
ANSWER:
In most of the passages where the word occurs, hell is just another name for the grave. When Jesus was buried he was laid in "hell", and when he was raised from the dead he came out of "hell".
See Ezekiel 32:27-29; Acts 2:25-31.

4.2 But did not Jesus speak of hell as a place of fire and punishment?
ANSWER:
Yes, on a few occasions he did. The New Testament was first written in Greek; and the Greek word that the Lord Jesus really used when he spoke of hell fire - the word that has been translated "hell" in passages like Mark 9: 43-48 and Matthew 10:28 - is Gehenna. This is actually the name of a place on earth. Gehenna was a valley just outside Jerusalem, where Jerusalem's rubbish was destroyed by fires that never went out. Thus the Lord meant: God will destroy the wicked as completely and as surely as the fires of Gehenna destroy the rubbish of Jerusalem. When the Lord Jesus used the word "Gehenna", he was using a kind of parable, as he often did.