Hebrews 4:12-16 / Mark 2:13-17
The word "vocation" comes from the Latin word "vocare" which means "to call".
Whatever vocation in life we have embarked on is a response to a calling, whether the calling is to to the married life, to the priesthood or religious life, to the single state.
Every vocation is great, if greatly pursued.
Saul was called to be the first king of Israel. That was his vocation. He was also gifted to fulfill that vocation. But later he would waste it all.
Levi (or Matthew) was called by Jesus. His response was prompt and decisive.
But more importantly, he remained faithful to that vocation and to that call.
We are called to be Christians and our baptism is our response to that call from God.
At baptism we are immersed into the identity of Christ and hence we are called Christians.
That is our first and fundamental call, because from that call flows the various vocations in life.
The test of our calling comes when we are tempted to be lesser than we are called to be, in other words, the temptation to be selfish, self-centered, greedy, etc.
But it is precisely in the midst of temptations that Christ reminds us of our vocation.
He calls out to us, just as He called Levi.
And if we should fall, then let us hear again those words of Jesus in today's gospel: I did not come to call the virtuous, but sinners.