Like the thread, the grandmother is not always visible to the physical eye, as she chooses who can see her. For example, Lootie adamantly opposes the idea of the grandmother when Irene tells her and she never is able to see the grandmother. Curdie on the other hand is unable to see the grandmother, however once he is able to accept that his truths may not be the same as Irene's truths, the grandmother reveals herself to him. Not all believe in God, for they do not see Him. Believers in Him are able to see and accept Him as their own truth, thus making them visible in their lives.
Irene takes on a critical role as "the believer", similar to the role followers of the Christian faith carry out, although I believe she takes on a much more critical role than simply a believer. Throughout the novel Irene is referred to as "a real princess", implying that she exemplifies the traits in which a real princess would possess such as honesty, obedience, and trust similar to characteristics in which the ideal Christian believer also demonstrate. Such characteristics are some of the most significant traits that Jesus himself embodied. .
Jesus was called upon by God to spread His presence as a faithful and obedient disciple, much like the grandmother encouraging Irene to spread the word of her presence. Upon sharing the story of her grandmother with Lootie, Irene is mocked and called a liar, similar to the mocking and accusations Jesus faced when he attempted to share his story of God. Guided by her grandmother as the God-figure, Irene leads others to believing making disciples out of them as Jesus did with his twelve disciples. Despite the tribulations both Jesus and Irene faced, their faith never faltered. It is within those trials that Irene's beliefs and faith are tested and she finds spiritual maturity. .
When the grandmother acknowledges bruises and dirt covering Irene following her adventure in the tunnels to rescue Curdie, she takes it upon herself to bathe Irene.