What does "strengthening the churches" mean?
The Greek word is ἐπιστηρίζω
B1 This means to make stronger.
B2 It is used 4 times in the Bible.
B3 The trees in the Biosphere 2 fell under their own weight from etiolation and no stress wood. The wind causes the trees to grow this type of cells which strengthen the tree. Our word here has the idea of strengthening in this sense. The winds and battering from skeptics, enemies, false apostles, false prophets, and false teachers might overwhelm the local congregation, thus Paul wanted to return to the congregations and strengthen them.
How do we strengthen the churches/congregations?
B1 Many of the epistles written in the New Testament were written for this purpose.
B2 The congregations would be strengthened by
C1 Handling disagreements according to the Scriptures
C2 Handling misunderstood doctrine according to the Scriptures
C3 Correcting people who preach false doctrine.
C4 Correcting people preaching a wrong Gospel
C5 Warning about false teachers.
C6 Handling people who are at odds with each other
C7 Clarifying what was taught earlier (in their first visit)
C8 Preaching against sin that might have arisen in the church
C9 Encouraging the brethren to continue in the faith. Discouragement may come
D1 from persecution
D2 from trials
D3 from failures
D4 from successes
D5 from believing there is no success in their sharing the Gospel
D6 from seeing no answer from prayer
D7 from remembrances of past sin
D8 from still struggling over present temptation to sin
Christians and churches need strengthening today in the nearly overwhelming flood of false doctrine, false teaching, and false teachers. We are strengthened by reading and studying the Bible every day. We also need fellowship and prayer. Without this we might fail the faith.