The Gospel (Mt 13:24-30) shows us the practical way to live the Christian life.
He proposed another parable to them. “The kingdom of heaven may be likened to a man who sowed good seed in his field. While everyone was asleep his enemy came and sowed weeds all through the wheat, and then went off. When the crop grew and bore fruit, the weeds appeared as well. The slaves of the householder came to him and said, ‘Master, did you not sow good seed in your field? Where have the weeds come from?’ He answered, ‘An enemy has done this.’ His slaves said to him, ‘Do you want us to go and pull them up?’ He replied, ‘No, if you pull up the weeds you might uproot the wheat along with them. Let them grow together until harvest; then at harvest time I will say to the harvesters, “First collect the weeds and tie them in bundles for burning; but gather the wheat into my barn.”‘”
“God has sown good seed generously in His field, the world; He has sown grace and love, and the desire for total oblation, the ideals of an apostolic, religious, saintly life. But, in the midst of all this good, the enemy comes to sow evil. Why does God, permit this? To sift His servants as we sift grain, to test them.
Sometimes we are scandalized, seeing evil working its way even into the best places, seeing that even among God’s friends, among those who should be a source of edification to others, there are some who behave unworthily. Then we filled with zeal, like the servants in the parable. We want to remedy this evil and root up the cockle.
The cockle is spared, not because it is good but in order to save the wheat. In the same way God spares the wicked and does not destroy them, for the sake of the elect. When God asks us to endure with patience certain situations, as inevitable as they are deplorable, He asks for one of the greatest exercised of charity, compassion, and mercy.
He does not tell us to fraternize with evil, to make a league with the cockle, but He tells us to endure it with the longanimity with which He Himself endured it. Was there not a traitor among the Apostles? Yet Jesus wanted him among His intimates — and with how much love He treated him! Indeed one of the greatest opportunities for the practice of charity is offered us by those who by their conduct give us so many occasions for forgiving them, returning good for evil, and for suffering injustice for the love of God. Moreover, we should consider that, whereas cockle cannot be changed into wheat, it is always possible for the wicked to be converted and become good. Were not Magdalen, the good thief, and Peter, who denied Jesus, converted? “
(Divine Intimacy, Fr. Gabriel of St. Mary Magdalen, OCD)