There is only one source and norm for faith and practice. It is called the Bible.
The Bible is where we get our information about what God has done for the world in Jesus Christ. This does not make the Bible some magic book that fell from heaven. It is not above investigation. But the simple fact of the matter is that the Bible has always withstood the critique of scholars and skeptics. We may question the Scriptures as long as we are willing to accept the answer we receive.
As the Word of God, the Bible must be taken seriously. It must be read as a communication from God to His people. It may not be ignored by His people!
This means we must take seriously what we like from the Bible and what we do not like. We take joyfully the promises of forgiveness, life, and salvation. We must also take the rebukes and commands.
When the Lutheran Reformers were asked why people should obey the commandments if they are told that they can be saved by grace through faith, the Reformers had a simple and straightforward reply: "Because God said so." (AC VI) The Christian does not need any more motivation to do what God says than simply hearing His Word.
And the Bible is His Word.
One more thing on Scripture Alone: it would also be wrong, naive, and arrogant of me to assume that I was the first person to read the Bible, the first person to read it correctly, or the smartest person to have ever read the Bible.
Scripture is never read in a vacuum. The Bible has come down through the ages and has been interpreted through the ages in a steadfast and orthodox fashion by the saints who have come before us. Martin Luther never claimed to have been the discoverer of something new or innovative, but of something that had been obscured, that was known plainly in the Church for a thousand years and attested to by the saints.
When seeking the truth, seek the Bible. It is the Word of God, and as such can withstand all criticism. His Word endures forever.
[Tomorrow: We stand for the Communion of Saints!]