“Here am I Lord; I come to do your will (Ps 40:8-9).” The responsorial psalm for this Sunday provides both a perfect prayer and a good model for discipleship. What do we "need" to do to be good Catholics, good disciples of Jesus Christ? Simply present ourselves before God and do his will. Check out each of these verses from the psalm.
I have waited, waited for the LORD,
and he stooped toward me and heard my cry.
And he put a new song into my mouth,
a hymn to our God.
The ball is in God's court. Simply wait for him (“I have waited, waited for the Lord”) and he will give you what you are to do to follow his will (“and he put a new song into my mouth”).
Sacrifice or offering you wished not,
but ears open to obedience you gave me.
Holocausts or sin-offerings you sought not;
then said I, “Behold I come.”