By what means were the apostles delivered from prison?

Answer

"The angel of the Lord by night opened the prison doors, and brought them forth." Acts 5: 19.

How futile was all this?
How early does Paul say Timothy was instructed?
By what comparison is it shown that the heavenly sanctuary will he cleansed?
What proves that the law is an undivided whole?
Do they take any part in earthly things?
What will be the final doom of Satan and his angels?
When praying what must we do in order to be forgiven?

Questions & Answers are from the book Bible Readings for the Home Circle