'Letter' in the Bible

But the Jew {is one inwardly}, and circumcision [is] of the heart, by the Spirit, not by the letter, whose praise [is] not from people but from God.

But now we have been released from the law, [because we] have died [to that] by which we were bound, so that we may serve in newness of the Spirit and not in oldness of the letter [of the law].

I, Tertius, the one who wrote this letter, greet you in the Lord.