Our theological disposition toward the nature of Scripture is vitally important in relation to our spiritual formation and vocation. If one has a faulty view of Scripture, one’s entire spiritual foundation is faulty. A faulty foundation in a house will not always be immediately apparent, but it will erode and cause numerous unseen problems which grow bigger as time goes on. The same is true of a faulty foundation to one’s faith. While it may seem to the casual observer that one’s faith is built on a solid foundation, over time it will become apparent in the little things which grow into bigger things that there is a serious flaw in one’s understanding.
In discussing Irenaeus’ doctrine of the Trinity, González explains that to him exactly how the three persons of the Trinity exist and relate to one another is secondary to the simple fact that it does exist. Knowing it to be true and realizing what that means for us takes priority over full understanding. It becomes a matter of faith and heart knowledge rather than head knowledge. St. Augustine said, “Understanding is the reward of faith. Therefore, seek not to understand that you may believe, but believe that you may understand.” Faith must be built on a solid foundation yet faith must transcend reason. As Jesus said, “Because you have seen me, you have believed; blessed are those who have not seen and yet have believed” (John 20-29 NIV).
Understanding the historical and theological issues of the canon is important to one’s spiritual formation in how one accepts the truth of scripture, as well as the faith traditions which have been derived from scripture. Some become Christians by choosing to have faith even when reason tells them that faith is crazy. Some Christians have come to faith through a very reasoned search of both the Scriptures and the historical documents that establish Jesus Christ as a very real individual in history. Either way, the Bible itself often seems unreasonable until faith makes it reasonable. There are several theories regarding the inspiration of scripture that we can choose to believe, from fully inspired by God to the idea that the work of scripture is simply human achievement, to a more supernatural influence. However, the doctrine of inspiration, bestowing the Bible with a unique standing, is vitally important. It is only when one believes that the Scriptures are the inspired Word of God, as stated in 2 Timothy 3:16a, that correct spiritual formation has a proper foundation, as well as a guide for continued growth. From there, it then follows that the rest of 2 Timothy 3:16 will be appropriately understood, that ‘[Scripture] is useful for teaching, rebuking, correcting, and training in righteousness.” Without this proper understanding, Scripture could be interpreted incorrectly which would skew one’s spiritual formation into something contrary to what God intends for us.
Another key theme that affects one’s spiritual formation is tradition. McGrath tells us that there is a distinction between “tradition” and “traditionalism”. While traditionalism is a mindless obedience to past doctrines, tradition is the ‘living faithfulness of the church to the faith which it expresses.” Irenaeus believed that a core doctrine of teaching, life, and interpretation could be traced from the time of the apostles to his own period. He believed that it was this tradition that safeguarded the church from new doctrine, innovations and misrepresentations of biblical texts, ensuring fidelity to the apostolic teachings. As McGrath also states, “what Christians believe affects the manner in which they pray and worship, the manner in which Christians pray and worship affects what they believe.”
A final theme of discussion that of moral versus venial sin. I believe the Catholic distinction between mortal and venial sin truly has an overall negative impact on spiritual formation in today’s church. This may be a Catholic theology but it has penetrated the Protestant church more than we may realize. While many Protestants seem to believe that Catholics are not true Christians, they also do not realize how many of their current beliefs come from the Catholic church. My personal experience since becoming a Christian is that more churches hold the belief that there is a distinction between mortal and venial sins without actually articulating that belief in their doctrinal statements. James 2:10-11 states, “For whoever keeps the whole law and yet stumbles at just one point is guilty of breaking all of it. For he who said, ‘You shall not commit adultery,’ also said, ‘You shall not murder.’ If you do not commit adultery but do commit murder, you have become a lawbreaker.” He is not necessarily saying that all sins are equal (in that if you commit adultery, you have also murdered, lied, stolen) but rather that if you break any of these laws, you have sinned. You cannot pick and choose which laws to obey, you must obey all of them. There are numerous scriptures which can be taken to support the Catholic distinction between mortal and venial sins but I believe the bottom line for all of them is this: even the mortal sin is forgivable by Christ if one confesses and repents and even venial sin can lead one further and further astray unless one recognizes it, confesses and repents.
While he is in the flesh, man cannot help but have at least some light sins. But do not despise these sins which we call ‘light’: If you take them for light when you weigh them, tremble when you count them. A number of light objects make a great mass; a number of drops fills a river; a number of grains makes a heap. What then is our hope? Above all, confession…. (St. Augustine, In Eucharist Prayer, Jo. 1, 6; PL. 35, 1982). 
My experience with those who seemed to have adopted the belief that there are varying levels of sin is that those sins they consider to be ‘mortal’ sins are not forgivable and those sins they consider to be ‘venial’ do not matter and can be knowingly committed over and over. This hinders true spiritual formation as one is led astray into believing that some sins are acceptable and can be overlooked. At the same time, those who have truly repented of their sins are considered unworthy because their sins are unforgivable. True understanding requires us to remember Romans 3:23, “for all have sinned and fall short of the glory of God.” All have sinned, all must repent, but all may be forgiven by the sacrifice of Jesus Christ. It is important for us to remember daily the grace God extends to us.
As 2 Timothy 3:16-17 states, scripture is “useful for teaching, rebuking, correcting and training in righteousness.” We must constantly align our thoughts and actions with Scripture to be sure that we are standing on a firm foundation and we must be willing to use scripture to correct and teach our brothers and sisters (in an appropriate way), as well as ourselves, for the same purpose.
 González, Justo L. Christian Thought Revisited: Three Types of Theology. Maryknoll, NY: Orbis Books, 1999, 28.
 “I Believe in Order to Understand”, Carpe Diem Coram Deo, assessed December 20, 2016, https://carpediemcoramdeo.wordpress.com/2009/05/19/i-believe-in-order-to-understand/
 McGrath, Alister E. Christian Theology: An Introduction. 5th ed. Oxford, UK: Blackwell, 2011, 135-137.
 McGrath, pg 139
 Ibid, pg 137
 McGrath, pg 142
González, Justo L. Christian Thought Revisited: Three Types of Theology. Maryknoll, NY: Orbis Books, 1999.
“I Believe in Order to Understand”, Carpe Diem Coram Deo, assessed December 20, 2016, https://carpediemcoramdeo.wordpress.com/2009/05/19/i-believe-in-order-to-understand/
McGrath, Alister E. Christian Theology: An Introduction. 5th ed. Oxford, UK: Blackwell, 2011.
Ndaro, Lucas “Scripture II” (audio of lecture, Evangelical Theological Seminary, Myerstown, accessed November 16, 2016, https://vimeo.com/191836976/24849d31c5).
Ndaro, Lucas “Catholic Theology II” (audio of lecture, Evangelical Theological Seminary, Myerstown, accessed November 22, 2016, https://vimeo.com/192702227/c2440f4297).