St. Ambrose of Milan

Just a quotation of St. Ambrose of Milan:

The Church of the Lord is built upon the rock of the apostles among so many dangers in the world; it therefore remains unmoved. The Church’s foundation is unshakable and firm against assaults of the raging sea. Waves lash at the Church but do not shatter it. Although the elements of this world constantly beat upon the Church with crashing sounds, the Church possesses the safest harbor of salvation for all in distress.

 I'm not sure from where this quotation comes, but I got it on this website