3. Christ “loved the Church and gave himself up for it to make it holy” (Eph 5:25-26) and he united the Church to himself as a bride.”(See Rv 19:7.) He filled it with his divine gifts, [See Eph 1:22-23. Lumen Gentium no. 7] because it is his Body and his fullness; through the Church he spreads truth and grace upon all.
Scripture forms the basis for the Catholic belief of the Church as holy. Yet individual members are not yet perfect in this regard:
The members of the Church, however, are exposed to temptation and often fall into the wretchedness of sin. As a result, “whereas Christ, ‘holy, harmless, undefiled’ (Heb 7:26), knew no sin (see 2 Cor 5:21) but came solely to seek pardon for the sins of his people (see Heb 2:17), the Church, having sinners in its midst, is at the same time holy and in need of cleansing, and so is unceasingly intent on repentance and reform.” [LG 8]
Compared to the witness of Christ, the Church offers “faithfully though darkly” the witness for other human beings. The continual emphasis on reform is not a function of a need to change for the sake of change, but a recognition that each human being is always in need of purification and deeper holiness. In this mortal existence, we can’t ever hope to achieve the perfection exemplified by Christ.