"Faith without works is dead" is a common reason I hear from the LDS and other works based salvation religious systems to justify their theology. The questions are: are they right? is it biblical? and how do I respond to this text?

Remember a text, taken out of context, is a pretext. Be studiers of the word!

Gal. 2:21 “I do not nullify the grace of God, for if righteousness comes through the Law, then Christ died needlessly.”