The First Reading, from the first Book of Samuel 16:1b, 6-7, 10-13a, contains, at best, oblique references to the other two readings. The anointing of David as king may be a reference to the anointing in the responsorial psalm both of which may refer to Christ the good shepherd. The figure of David may also be a prefigurement of the anointing to Messiahship of Jesus for his mission. .

The Second Reading from the Letter of St. Paul to the Ephesians 5:8-14 is particularly significant because throughout the season of Lent the community has been urged to cast aside deeds of darkness and walk in the brilliance of the light of Christ. In this reading, for the first time during Lent, the darkness-light theme which will be so predominant at Easter is enunciated. The believer must leave the deeds of darkness and live according to the justice and truth of God through the light of Christ. 

The Gospel reading from John 9:1-41, dominates the liturgy by the length of the reading and its significance. Already, in Old Testament Revelation, the Lord God had shown the People of Israel how the justice of the Creator was so much more profound and true that the thoughts of men. We have, in fact, heard in the first reading ‘God does not see as human beings see; they look at appearances but the Lord looks at the heart.' (1 Sam 16:76). The Lord pointed out in this way the true, unique, criteria on which men are judged.  Read more here..