How do Protestantism and the LDS Church differ as to what is required for a believer to attain salvation and eternal life? What is the difference between what Protestantism and the LDS Church teach about what is needed to attain salvation and life in eternity?

Good answers will summarise the doctrines of both with quotes from official sources and with some scriptures which are used to support those positions.
Protestants believe in Five Solas for how salvation is attained:


Sola Fide, by faith alone.


  To teach that besides faith in Christ other devices like works, or the
  observance of rules, traditions, or ceremonies are necessary for the
  attainment of righteousness and everlasting life, is to make Christ and His
  salvation of no benefit to anybody. 1

Sola Scriptura, by Scripture alone.


  What is asserted without the Scriptures or proven revelation may be held as an opinion, but need not be believed.2

Solus Christus, through Christ alone.


  A new creature is one in whom the image of God has been renewed. Such
  a creature cannot be brought into life by good works, but by Christ alone. 3

Sola Gratia, by grace alone.


  teaches that we must be saved solely by the grace of God 4

Soli Deo Gloria, glory to God alone.


  So, whether you eat or drink, or whatever you do, do all to the glory of God.5



So no action, ritual, or thing that you do helps because God's grace doesn't depend on our works. Some Protestants believe once you're saved there is nothing you can do to jeopardize your salvation. Others believe it is possible to lose it.



The LDS believe there are two parts of salvation:


Physical salvation


  All people eventually die. But through the Atonement and Resurrection of Jesus Christ, all people will be resurrected—saved from physical death.6

Spiritual salvation - you are saved after all that you can do. You show your faith by works/actions (James 2:17-26, Salvation by Grace or by Works)


  Salvation from Sin. To be cleansed from sin through the Savior's Atonement, an individual must exercise faith in Jesus Christ, repent, be baptized, and receive the gift of the Holy Ghost. Those who have been baptized and have received the Holy Ghost through the proper priesthood authority have been conditionally saved from sin. In this sense, salvation is conditional, depending on an individual's continuing in faithfulness, or enduring to the end in keeping the commandments of God 6,7



For a more in-depth response to LDS belief on salvation refer to this answer.



The difference is that Protestants don't believe anything a man does matters as long as he follows the five solas (faith, scripture, Christ, grace, and glory to God alone) he is saved. The LDS believe that if you have faith you will repent, be baptized, receive the Holy Ghost, and endure to the end; then you will be saved by grace.



All emphasis was added

1 http://www.online-literature.com/martin-luther/epistle-to-the-galatians/5/, Ephesians 2:8

2 http://www.christianitytoday.com/history/issues/issue-34/dr-luthers-theology.html, Romans 15:4, 2 Timothy 2:16

3 http://www.online-literature.com/martin-luther/epistle-to-the-galatians/6/, Acts 4:12, Hebrews 7:25, Romans 8:34

4 https://reformedreader.wordpress.com/2011/03/15/luther-on-grace-alone-sola-gratia/, Ephesians 2:8

5 http://www.biblestudytools.com/esv/1-corinthians/10-31.html

6 https://www.lds.org/topics/salvation?lang=eng&amp;old=true, 1 Corinthians 15:22

7 Acts 2:37-38, 2 Peter 2:20-22, John 3:5