WRITER, the Apostle Paul. 
MAIN THEME. This is somewhat hidden, but it is quite apparent that Paul had prominently in mind, the vindication of his apostleship when he was writing this book. Both epistles to the Corinthians indicate that there was an element in this church which tended to discredit his ministry and authority. This tendency is shown in the texts of the Key Chain below.
CONTENTS. This is one of the most personal of all of Paul's epistles. He dwells largely upon his own ministry. He opens his heart and discloses his motives, his spiritual passion, and his tender love for the church.
KEY CHAIN.
2Co 3:1 5:12 7:2 10:2,3 11:5,6 12:11 13:3
SYNOPSIS: There are no definite divisions of thought in the epistle, but the subject matter may be arranged under three headings.
I. The Characteristics of the Apostle's Ministry.
(1) Comforting
2Co 1:4-7 7:7,13
(2) Suffering
2Co 1:5-9 4:8-12 5:4 6:4-10 7:5 11:24-28 12:7-10
(3) Sincere
2Co 1:12 2:17 4:2 7:2
(4) Steadfast
2Co 1:17-19 4:1,16
(5) Solicitous
2Co 2:3,4 7:7,8 11:2,3 12:20,21
(6) Triumphant
2Co 2:14 4:8,9 12:10
(7) Self-sacrificing
2Co 4:5,11,15 5:13 11:7,9
(8) Love of Christ the controlling motive
2Co 4:11 5:14
(9) Spiritual
2Co 4:18 5:16 10:4
(10) Persuasive
2Co 5:11,20 6:1 10:1,2
(11) Reconciling
2Co 5:19-21
(12) Demonstrated by earnestness, afflictions and good works
2Co 5:13 6:4-10 12:12
(13) Authoritative
2Co 10:1-11
(14) Self-supporting
2Co 11:9
II. Exhortations and Instructions concerning Benevolence chs 8,9
2Co 8:1 - 9:1
III. The Apostleship of Paul.
(1) Discredited by one element in the church
2Co 10:7-10 12:11 13:3
(2) The authority of
2Co 2:9 13:2
(3) Authenticated:
(a) By the Lord
2Co 1:1,21,22 3:5,6 4:6
(b) By unparalleled sufferings for the cause
2Co 6:4-10 11:23-27
(c) By wonderful revelations received
2Co 12:1-5
(d) By mighty deeds performed
2Co 12:12
CHOICE SELECTIONS
(1) The ideal ministry
2Co 4:1-18
(2) The triumph over death
2Co 5:1-9
(3) The call to separation from the world
2Co 6:14-18
(4) The list of sufferings endured by Paul
2Co 11:24-33
(Outline
from Thompson’s Chain Reference Bible)