What are the similarities and differences of Lutheran theology compared with Baptist theology?
I am not an expert on either Baptist or Lutheran doctrine. What I will give is a summary of what I have been able to find through research into what each of these groups say about their own beliefs. I also preface many statements with qualifiers like “many” or “most” because, being two of the largest non-Catholic denominations, each group is split over certain doctrines.
The authority and inspiration of the scriptures (although some Lutherans deny the infallibility of the Bible). Baptists tend toward a strict literalness in interpreting scripture, while some Lutherans accept a more fluid interpretation. Luther, himself, rejected parts of the book of James as being a “gospel of straw.”
Baptism is essential for, but as a result of salvation. (Some Lutherans hold that it is essential in order to receive salvation.)
Either party of a divorce may, under certain circumstances, marry again.
Trinity: Most Lutherans and some Baptists hold that there is “one God in three persons.” Many Baptists believe that the doctrine of the trinity is not essential.
Sabbath Observance: Lutherans and most Baptists do not observe the Sabbath in the way that the Jewish people do. The Seventh Day Baptists, however, reject Sunday assemblies and working on Sabbath.
Baptism: Baptists believe baptism is necessarily immersion as implied by the original Greek word; Lutherans accept sprinkling and pouring as modes of baptism. Baptists believe that only adult believers are subjects for baptism; Lutherans practice baptism of infants as well as believing adults.
Divorce: Most Baptists believe that divorce should be for marital infidelity only; Many Lutherans believe that divorce can be for marital infidelity and other serious causes, such as abandonment or abuse.
The Lord’s Supper: Many Baptists only take the Lord’s Supper monthly, and reject the doctrine of sacraments. Most Lutherans take the Lord’s Supper weekly and consider it (and baptism) to be sacraments (that is, something that makes one holy in and of itself).
Calvinism: Lutherans generally reject the doctrines of John Calvin, which are the basis for Baptist doctrine. For example, Baptists believe that nobody is capable of goodness without the direct intervention of God; Lutherans believe everybody is born good, but sin. (However, Baptists reject the doctrine of “original sin” or “inherited sin,” while Lutherans generally accept it.) Baptists generally accept that there is no free will, while Lutherans insist that everyone has free will.
I have tried to answer your specific question. I have not answered what the Bible says about any of these doctrines. Please see It Is Believed for my previous study guide about major doctrines, and what different groups believe about each.