What is theology?

Among the Reformed figures, we find a lot of sound definitions of theology as below.


Before Ramus, Bucer defines the true theology as "the knowledge of living piously and blessedly (scientia, pie et beate vivendi)." For him, "the true theology is not theoretical or speculative but active and practical (vera theologia, non theoretica vel speculativa, sed activa et practica est)."
-- Martin Bucer, In sacra quatuor evangelia, enarrationes (1536), pp.549, 753. --


According to Ramus, theology is "the doctrine of living well, the whole and perfect doctrine of blessed life embraced in the holy books of each Testament (doctrina bene vivendi, totamque beatae vitae ac perfectam doctrinam sacris utriusque testamenti libris amplectitur)."
-- Petrus Ramus, Commentariorum de religione christiana (1576), I.i. --


Fenner's definition of theology is quite better than Ramus' that theology is "the knowledge of truth which is concerning God towards living rightly and blessedly (scientia veritatis quae est de Deo, ad recte beateque vivendum)."
-- Dudley Fenner, Sacra theologia (1585), I.i. --


Perkins defines that "theology is the science of living blessedly for ever."
-- William Perkins, A golden chaine (1590), I. --


Keckermann pay more attention to our salvation by defining theology as "pious prudence reaching into the salvation," "faculty and practical knowledge infused into the elect by God, which one may compare it with media that relates to piety, that is, union with God on which all our salvation rests (facultas et peritia hominibus electis a Deo infusa, qua possint ea media sibi comparare, quae pertinent ad religionem, id est, unionem cum Deo, in qua consistit omnis nostra salus)."
-- Bartholomäus Keckermann, Systema Theologiae (1602), I.i.1. --


Wollebius defines Christian theology as "the knowledge of God towards His glory and our salvation by recognition and worship (doctrina de DEO ad ipsius gloriam et salutem nostram cognoscendo et colendo)."
-- Johannes Wollebius, Compendium Theologiae Christianae (1626), p.1. --


Scharpius provides the etymological meaning of theologia as λόγος τοῦ Θεοῦ: given that λόγος may mean both ratio and oratio, theology is the Word of God (sermonem Dei) or the word about God (sermonem de Deo).
-- Johannes Scharpius, Cursus theologicus (1620), p.1. --


According to Wendelin, "theology is the doctrine of true religion or piety for the salvation obtained from the revealed God and the written Word of God entirely established in His glory (theologia est doctrina de vera religione ad salutem obtinendam a Deo patefacta et verbo Dei scripto plene consignata in eius gloriam)."
-- Marcus Friedrich Wendelin, Christianae theologiae (1634), prolegomena, I.ii. --


Mastricht regards Christian theoretical-practical theology as "the doctrine of living to God through Christ (doctrina vivendi Deo per Christum)."
-- Petrus van Mastricht, Theoretico-Practica Theologia (1699), p.1. --


Echoing Wollebius, Marckius defines Christian theology as "doctrine that hands over the true religion to humans, sinners, from the revelation of God for human salvation and the glory of God (doctrinam, quae veram religionem ex Dei revelatione homini peccatori tradit, ad hominis salutem Deique gloriam)."
-- Johannes Marckius, Compendium theologiae christianae didactico-elencticum (1716), I.xxvii. --


A simple definition of theology made by Reformed thinkers, like Junius and Alsted, is "the knowledge of divine things (rerum divinarum scientia)." Slightly different, Polanus prefers the definition of true theology as "the wisdom of divine things (sapientia rerum divinarum)."
-- Amandus Polanus, Syntagma theologiae christianae (1615), I.ii. --


On the basis of Romans 11:36, Aquinas made a beautiful statement that "theology is taught by God, teaches of God, and leads to God (Theologia à Deo docetur, Deum docet, & ad Deum ducit).
-- Thomas Aquinas, Summa theologiae, I.i.9. --