To determine a word’s meaning, we use a dictionary. The dictionary often gives us several definitions, and we pick one out according to the context of the word we’ve read. So the meaning of a word is based on context and identity (definition).
When we say a gesture means a lot to us, it is because it has importance and applies to us in a specific way, at a specific time, in a specific context.
When we have a meaningful relationship with a person, it is because we share many meaningful things with him or her. We are within one another’s context. A husband and wife share children, who, as persons, have a great capacity to provide meaning.
It is unjust when a thing has the identity and context to mean a great deal to us, but doesn’t. Ignoring one’s children is an injustice of this kind.
There is a network of things that ought to mean a great deal to us, and a network of things that actually mean a great deal to us. The more these two networks are in sync, the more true meaning we have in our lives.
Our network of valid meaning is both determined for us and by us. We may choose to have children, but we don’t choose who our children are. It is a matter of responsibility (justice) to accept the aspect of our choice that we did not determine.
For Christians, the Word of God is the "meaning of life." He is the Creator of the network of meaning, “without him was made nothing that was made,” and he is the cornerstone of meaning itself, “in Him all things hold together.” (Jn 1:3; Col 1:17).
For something to be meaningful, it must point beyond itself: A word is always spoken about something; a person discovers meaning when he dedicates himself to some cause; the Word of God points to the One who spoke Him, the Father. Our “meaning of life” is the thing toward which our whole being points.
According to the word of God, a person is in the image of God. His very existence, then, points to God, and all his meaning comes from God. This is a part of the network of meaning he has not chosen. It is up to him to choose God as the meaning of his life.