Solas

The 5 solas of the Protestant Reformation, from which came Protestantism, are also known as the 5 pillars. They are as follows: (in Latin with the English to the right)

Sola Scriptura (Scripture alone)

Sola Gratia (Grace alone)

Sola Fide (Faith alone)

Solus Christus (Christ alone)

Soli Deo Gloria (Glory (to God) alone)

“Alone” does not mean “me” nor my interpreting without prayerfully considering what the Scriptures state in their proper context. Instead, “alone” emphasizes that pillar without adding to it. So “Sola Scriptura” would mean the texts of the Bible in its entirety without adding additional texts to it. 

I find “in Scripture alone” to be one of the most important pillars to understanding the Christian faith as it is in the Bible and reading it in its entirety that you can find each of the other 4 pillars. As such, if we claim ourselves to be Christian, we must be in the Word of God, the Scriptures. As we do so, we find out more about God, ourselves, and thereby the other 4 pillars which also brings God glory as we acknowledge His importance (involving the 5th pillar above) in our lives.
This is just a brief introduction to the 5 Solas. For further reading, I’d suggest the following:

https://www.monergism.com/search?keywords=5+solas&format=All 

Discipleship

“Discipleship is a process which enables you to “grow up” in the Lord Jesus Christ and equips you to overcome joyfully the pressures and trials of this present life (based on Luke 9:23-24; James 1:2-4). Discipleship requires constant self-examination that is in accordance with God’s Word (based on Matthew 7:1-5; I Corinthians 11:31; Galatians 6:4).”

– p. 35 of Self-Confrontation: A Manual for In-Depth Biblical Discipleship, developed by John C. Broger