'Because thou sayest, I am rich, and increased with goods, and have need of nothing; and knowest not that thou art wretched, and miserable, and poor; and blind, and naked." ~ Revelation 3:17
This is the heart of Christ's rebuke of the church at Laodicea, the "lukewarm" church (v.16) of the last days. This is an evangelical church for its candlestick is still in place (note Revelation 1:20; 2:5), but it has become a neutral church, "neither cold nor hot" (3:15). The reason for its tepid witness is because it has become "rich, and increased with goods," comfortable in a culture which tends to equate material prosperity with success and God's favor. It may have acquired large and beautiful facilities, developed special programs of many kinds, featured a variety of musicians and other artists, and even gained a measure of political power. Yet, Christ calls it poor and blind and naked!
Not all large churches become like this, of course, but it is always a real danger. The desire for large congregations can easily lead to compromising biblical standards of doctrine and practice. "Woe to them that are at ease in Zion," the prophet warned (Amos 6:1).
Note that the Lord began His letter to the Laodicean church by identifying Himself as "the Amen, the faithful and true witness, the beginning of the creation of God" (Revelation 3:14). This strongly suggests that a major reason for the development of such complacency in a large church (or a small church, for that matter) is neglect of these three doctrines-- the sufficiency of Christ, the inerrant authority of God's Word, and the special creation of all things by God.
The letter to this church ends with the sad picture of Christ standing at its door, seeking admission (v.20). "He that hath an ear, let him hear what the Spirit saith unto the churches" (v.22).