When trying to understand the evangelist's message we need to examine the symbolism he uses. The situation here is the time after the resurrection when the church waits for the return of the bridegroom, Christ. The early church expected Christ to return soon but he seemed to be delayed. The story would form a sermon in that early church warning people to not become lax, but to remain vigilant.

God is light (1 John 1:5), and Christ is the light of the World. (John 1:1-5,9)(cf. 2Cor 4:4-6) The virgins are the community members who maintain that light in the world working against the darkness of ignorance and sin. They have the light because of grace through baptism (Ps 18:28) and make it visible by faith and the charity that faith prompts (James 2:14-18). The oil may represent the grace that provides the light. The danger is that people will allow that grace to dwindle, to be depleted, perhaps by sin or inaction. Perhaps the falling asleep could mean that even the wise virgins have become discouraged but they have not allowed the store of grace to drop too low. Their fidelity to faith and charity even if discouraged has allowed them to have enough grace, oil, to continue to wait and work.

The message from situation of the foolish virgins is important to Catholics. It is easy enough to allow oneself to loose grace through sin or indifference. When suddenly that person realizes that Christ is coming for them in death they want to rectify the situation but it may be difficult. The sacraments of penance and anointing of the sick can only be performed by a priest or bishop and one may not be available at the last minute. Their situation is like that of the foolish virgins who try to go and buy oil late at night from merchants who are not longer available. The message of the parable to be alert and be ready is powerfully important to everyone. Do not think you have a lifetime to fix a spiritual problem. You should spend your lifetime becoming ready to receive Christ's call to you to come home.