Concept of " Spiritual Discernment"
Hello my spiritual friend,
In my last notation, I spoke of the third rung, I would be amiss, if I did not ensure that you appreciated a particular aspect of it; DISCERNMENT.
Understandably, this topic is unfortunately, one of the least discussed, and appears certainly not at the top of Apostle Paul's spiritual gifts list. Nevertheless, I could not recommend any other gift by which you may seek and obtain from God. Fortunately, this is what Solomon had asked God for and received.
Now as to the subject matter, the following is what shall be used in new "Rare Works" release, "Great Works" by Jean Gerson, to be issued by the end of this years, 2011.
This term is found frequently in the two of Gerson's under discussion. Etymologically, discretio is a Latin noun formed from the verb cerno and the prefix dis. Cerno takes its origin from the Greek verb krino which means to sift, to separate by a sieve; hence, to separate the true from the false, to discern, to distinguish, to judge. The prefix dis or di in the Latin, or dia in Greek, indicates separation or division used as a prepositional prefix; sometimes also signifies a negation.
In Christian theology this term and concept originated with Paul who used the Greek word diakriseis in identifying charism of the "discernment of spirits",  which term then became a part of the language of Christian theology. It appears three times in his epistles. Now in the two cases it is translated in the Latin as discretio,  and as disceptatio in the third instance.  In First Corinthians, it has the meaning of discernment of spirits; while in the Epistle to the Hebrews it has the meaning of discernment between good and evil. Now up until the fifth century the early Christian writers Paul's term to designate the discernment of spirits. However, after that time "discernment" (discretio) also took on ‘to judge with moderation, with prudence'. 
Definition of Discernment of Sprits
In theological terminology the discernment of spirits has a threefold meaning:
1) the charism identified by Apostle Paul;
2) the supernatural virtue of prudence or discretion;
3) the skill or knowledge acquired by experience or study to discern whether a person is moved by natural, supernatural, or diabolical influences.
St. Thomas does not discuss discernment of spirits in detail; he instead discusses charisms or gratuitous graces and then chooses that of prophecy to discuss at length. He places the gratuitous graces into three categories:
"With regard to gratuitous graces, which are the first objects to be considered, it must be observed that some of them pertain to knowledge, some to speech, and some to operation. Now all things pertaining to knowledge may be comprised under prophecy, since prophetic revelation extends not only to future events relating to man, but also to things relating to God, both as to those which are to be believed by all and are matters of faith, and as to yet higher mysteries, which concern the perfect and belong to wisdom. Again, prophetic revelation is about things pertaining to spiritual substances, by whom we are urged to good or evil; this pertains to the discernment of spirits. Moreover it extends to the direction of human acts, and this pertains to knowledge, as we shall explain further on." (Q. 177) . 
Bro. Smith SgS
 1 Cor. 12:10
 See 1 Cor..2:10, and Heb. 5:14. It is noted that Hebrews is now considered not to be by Paul.
 See Rom. 14:1
 Cabassut, Andre, "Discretio," DS, 3, 1311-12. 12
 See ST, IIa IIae, Q.171. Note, Thomas does not add anything new from his commentary of Corinthians.