“Behold, I send you out as sheep in the midst of wolves; so be wise as serpents and innocent as doves.” –Matthew 10:16
The late author and preacher Peter J. Gomes (1942–2011) considers the type of seasoned innocence to which Jesus calls his disciples:
You need both innocence and experience, both the serpent and the dove, if you have any chance of making it as a Christian in this world. Innocence without experience eventually becomes a state of pure illusion, and experience without vision deteriorates into cynical despair. . . .
When Jesus speaks of the wisdom of the serpent he is not giving us an invitation to cynicism; he wants us, like the serpent, always to know what is going on. Of all creatures, the serpent is the one most aware of his environment, most sensitive to his surroundings, most in touch with his circumstances, for his entire body is a live wire of sensation. We are meant to be aware, heads up, eyes open, mind on full throttle, not easily fooled or seduced by the blandishments of this life. . . .
To be innocent as a dove is an exercise neither in naïveté nor in deception. The dove is the symbol of the spirit of God, and where the dove is, there is to be found serenity, reconciliation, and peace. When Noah wanted to know if it was all right to go back into the world, he didn’t ask for a weather report; he sent out for the dove. When Jesus was baptized, God’s favor was shown in the descent of the dove; and the Holy Spirit, the present tense of God, is represented in Christian art by the dove. Give me the dove any day; the dove is no dumb bird.
In other words, Jesus tells us that to survive in this world . . . we need to know what is going on and not be overwhelmed by it; and to do that we need to live all of the time in a divine and creative dialogue between innocence, the first and last love of our faith, and experience, by which we learn what we need to know. 
Father Richard describes these deeper stages of spiritual maturity as a “regained innocence”:
There is a regained innocence, which could also refer to the highest states of enlightenment. This is the clarity and freedom found in a person who has been deeply wounded but, after passing through a healing purification, comes out the other side with the best of both worlds; they are cleverly wise and yet not overly defended or guarded. I suspect this is exactly what Jesus represents and what he describes when he tells his disciples to “Go forth wise as serpents but innocent as doves” (Matthew 10:16). This would be those who have left the Garden, eaten a few more apples, and returned again because they now know how to live and love both inside and outside of the Garden. 
 Peter J. Gomes, “Innocence and Experience,” Strength for the Journey: Biblical Wisdom for Daily Living: A New Collection of Sermons (San Francisco, CA: HarperSanFrancisco, 2003), 102, 103, 104.