Applying the 21/90 rule to reading scripture. Ever heard of the 21/90 rule? The 21/90 rule (first named by Dr. Maxwell Maltz in 1960) asserts that practicing a personal goal for 21 days straight followed by consistency over another 90 days results in a lifestyle change. 120 DAYS!! That’s where many of us are. 120 days of reading God’s Word. And, more than that … reading God’s Word together and chronologically toward understanding God’s Story, OUR story.