The Church is the "pillar and support of the truth" (1 Timothy 3:15). What are the most essential truths we are required by God to support and uphold? Important answers are 500 years old.
1 - do you know what happened?
2 - five principles to stand upon
a - sola scriptura (scripture alone)
b - sola fida (faith alone)
c - sola gratia (grace alone)
d - solus Christus (Christ alone)
e - soli Deo gloria (glory to God alone)