Who is Martin Luther and why is he so important to Lutherans? God's great gift is his Word. Throughout its history the Christian church has had to struggle to proclaim and teach the truth of God's Word. Toward the end of the Middle Ages (in the 15th and 16th centuries), serious false teachings and abuses had developed in the church. God in his grace chose Martin Luther to be his servant for a most important work: the reformation of the church.