Lutherans refuse to baptize only by immersion, so as not to give into legalists who demand that baptism is only valid by immersion.
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Perhaps Paul's definition of a legalist and your definition are different. If so, then you are still on the wrong side of the fence Biblically.
The mode of baptism is not what matters. It is what God does in baptism that matters.
The mode of baptism matters greatly. As I have pointed out the EOC still immerses. They have no choice. They understand what the word "baptidzo" means. It means to immerse, not sprinkle or immerse. It has only that one definition. The NT was written in Greek. Why would a Greek speaking church still immerse? Because that is what the word means. Every time they read that word they read "immerse," and thus they do. They don't have any other choice but to obey. You can't substitute sprinkle and pour for immerse. It doesn't work.
It didn't work for Adoniram Judson either. He was America's first foreign missionary, but could read Greek fluently. Supported by the Congregational Church of America he set out with plans to help William Carey. While crossing the Atlantic he was reading his NT in the Greek. He could not get away from this fact and teaching that baptism is by immersion for that is what the word means. He became convicted, wrote back to the Congregational Church, and told him he must change his convictions on the matter of baptism. He ended in India with no support. Ultimately he ended being the first missionary to Burma.
The argument has been put forth that baptism is a pledge. I don't buy into that. Baptism is symbolic. It is purely symbolic. What does baptism do for a person? It gets them wet. Those particles of hydrogen and oxygen are not supernaturally going to make you more holy, give you more grace, regenerate you, or any of the such. Those who believe those things are superstitious, as superstitious as the Hindus in India who believe that washing in "the holy waters of the Inudus River" will wash away their sins. The RCC teaching is no different. It is just as superstitious. It teaches the same thing.
Jeremiah 2:22 For though thou wash thee with nitre, and take thee much soap,
yet thine iniquity is marked before me, saith the Lord GOD.
--Scrub harder Jeremiah mocks; maybe you will be able to wash away your sin. No. Frankly he says
your sin is marked before me! and "baptism" even with soap cannot wash it away. What a mockery!
Romans 6:3 Know ye not, that so many of us as were baptized into Jesus Christ were baptized into his death?
4 Therefore we are buried with him by baptism into death: that like as Christ was raised up from the dead by the glory of the Father, even so we also should walk in newness of life.
--Paul was writing to believers. He was writing to those who had put their faith and trust in Christ. Then those same ones, after salvation were baptized.
Verse four says: We are buried by baptism into death. Christ died. We (in picture must die). We die to our old life of sin. Christ was buried. We go under the water completely as Christ was completely buried. When the preacher holds you under the water he doesn't leave you there. You don't drown.
"Like as Christ was raised up from the dead by the glory of the Father even so we also should walk in newness of life."
Coming out of the water symbolizes our newness of life in Christ. It is a new life. Old things have passed away behold all things are become new.
Only baptism by immersion can fulfill this picture.
Only baptism by immersion can also give the symbolic picture of the death burial and resurrection of Jesus Christ.
Here is the true meaning of baptism. It is not simply a pledge or public profession. If it were, who was the Ethiopian Eunuch publicly proclaiming his faith to?
No, it was the first step of obedience in the Christian life that symbolized the Christians death to his old life and a walk in newness of life in Christ.
We do it because we are commanded to by Christ.
What does it do "for" us? It makes us wet.