Q and A 1. Author's warning against immaturity: it is hard to explain because we are slow to learn. We need milk, not solid food, everyone who needs milk, be still an infant. Solid food is for mature. Who by constant use have trained themselves to distinguished good from evil. Laying of hands is the foundation of repentance from acts that lead to death.
Q and A 2. Author's warning against falling away: if they fall away to be brought by repentance, because to their loss they are crucifying Jesus all over again and subjecting him to public disgrace. In danger of being cursed, it would be burned. Show diligence to the very end, to make our hope sure.
Q and A 3. How can we be certain that God's promise come to pass: God made his promise to Abraham, no one is greater than him to swear by. MeN swear by someone greater than themselves. An oath confirms what is, and put and to all arguements.