A Seventh-day Adventist told me that, when a person dies, he is asleep and is aware of nothing. Does the Bible really teach this?
No. Those who hold to “soul sleep” assert that once a person dies, he enters a state of unconsciousness until the Second Coming. Some use this claim to argue that saints can’t intercede for us, since they supposedly are asleep.
Isaiah 14:9-10 tells us that the dead are agitated and are speaking. 1 Samuel 28 tells of Samuel conversing with Saul after his death. In 1 Peter 3:19, Jesus preaches to souls in prison. Why preach to sleeping spirits? Talk about a bored audience! Try telling the rich man in the story of Lazarus and the rich man (Lk 16:19-31) not to worry, since he is just sleeping.
If the dead are asleep, one must ask how Jesus communicated with them during his transfiguration (Mt 17:3), how they offer our prayers to God (Rv 5:8), how they cry out in a loud voice in praise of God (Rv 7:10), and how these sleeping, unconscious souls cry out, “How long will it be, holy and true master, before you sit in judgement and avenge our blood on the inhabitants of the earth?” (Rv 6:10). That is a pretty windy statement for someone asleep! Those that have died are more alive than we are, and they surround us like a great cloud of witnesses (Heb 12:1).