The four sources of theology that Alister McGrath lists in Christian Theology – An Introduction (2011) are as follows: scripture, tradition, reason and religious experience (p.120).
Jan-Olav Henriksen doesn’t use these exact divisions in his exposition on dogmatics, Guds virkelighet (God’s reality), but the subject matter is there underneath nonetheless. The four sources of theology are not exactly sources for him, but rather facets.
Scripture is the basis of theology (24) as both the New and the Old Testament tells us of God’s appearance in history for the salvation of mankind, which is the main point in theology. The root of all theology lies in the Gospels as Jesus is God as He relates to man (18f). Henriksen adds to that the church and every Christian individually need to think about and formulate what they believe in, so creed is closely related to Scripture, though it is not an authority in itself (49). Creed is the glasses through which we read scripture, and we must be aware of them (25).
Tradition is the means by which central Christian beliefs are kept alive (50) but can only be allowed to guide us if it adapts to the present, in dialogue with other traditions. Henriksen warns against traditionalism, where the church simply reproduces the old days today (20f). Tradition in its best is like grammar, it guards against misunderstandings (25). Tradition also has many facets one of which is in fact Scripture thus tradition should not be abolished (48ff).
Henriksen considers theology rational in the sense that it must be consistent with itself. Reason is not above theology, but theology must be reasonable in its own field (24). At the same time, Christianity doesn’t rise and fall with to science unreasonable details like seven-day creation which thus doesn’t need to be upheld (28f). Henriksen gives theology the uppdrag to be in constant dialogue with its surroundings as well as to always reconfirm itself and the practices and beliefs of the church. For this, reason is necessary but only as a supplement to theology, not as a rationalistic ruler (30).
Religious experience is primarily when God reveals Himself, which we have knowledge of through scripture(19). Another type of religious experience is living in God’s reality, which according to Henriksen, is all reality. So a non-Christian experience is also from God and should be respected (29). However, religious experience can be fully understood only in light of revelation and Scripture, not the other way around. To Henriksen it is not important what we feel about Scripture, but what Scripture says about what we feel. At the same time our experience can make Scripture true for us so it is still important. On the other hand, theology still goes beyond our experience, we must have faith without proof (22f).
Please stay tuned for subsequent parts!