Why Does God Allow Suffering?
If we apply the simple fact that we serve God, not God serves us, we cannot fail in prayer. Jesus also in His prayers (also in what he taught his disciples to pray - Our Father who art in heaven) includes that the Father's will be done. So whatever we asked for in our prayer, we give God the right to override it.
Why did God appear on the mountain? To give His law to the people! And why did He appear in a fire? Because what comes from this world cannot survive the fire of God. Because there is nothing in this world that can survive in the presence of God! Therefore, we either obey His word and may have fellowship with God, or we disobey, but then His fire consumes us.