'Simple' in the Bible

And though by this time it would be right for you to be teachers, you still have need of someone to give you teaching about the first simple rules of God's revelation; you have become like babies who have need of milk, and not of solid food.

By faith he kept the Passover and the sprinkling of the blood [on the doorposts], so that the destroyer of the firstborn would not touch them (the firstborn of Israel).