In his letter to the Ephesians, Paul uses images, such as a house and its household to emphasise the close and unique relationship that exists between God and His people. According to Paul, all believers form part of the household of God, of which the apostles and prophets are the foundation, and more importantly, Christ is the cornerstone. A cornerstone is described "a stone that forms the base of the corner of a building" or "the first stone set in the construction of a building". A cornerstone is important because all other stones are set in reference to this stone, and therefore, it determines the position of the whole structure.

In real life, however, we hardly pay attention to the cornerstone of a building. For example, people who wish to purchase a house will look closely at its external and outstanding features. Usually, they would not ask about, or wish to look at the cornerstone. The reason being the stone is not visible to the eye as it is not a prominent feature of the house. Something like this may take place in our faith journey. Most of us may say that Jesus Christ is the "cornerstone" of the Church but in reality, may not be making him the centre of our lives. After all, Jesus, like the cornerstone, is not visible to the eye, and we, like Thomas, who wants evidence that Jesus has resurrected, may believe only what we see. This is why it is good for us to be reminded by Jesus that, "Happy are those who have not seen and yet believe."