Meaning: To follow intructions exactly.
Matthew 5:18
For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled.
Luke 16:17
And it is easier for heaven and earth to pass, than one tittle of the law to fail.
Romans 2:29
But he is a Jew, which is one inwardly; and circumcision is that of the heart, in the spirit, and not in the letter; whose praise is not of men, but of God.
Romans 7:6
But now we are delivered from the law, that being dead wherein we were held; that we should serve in newness of spirit, and not in the oldness of the letter.
2 Cor. 3:6
Who also hath made us able ministers of the new testament; not of the letter, but of the spirit: for the letter killeth, but the spirit giveth life.