Mark says that Herod was very disturbed when he heard John the Baptist speak but that he felt the attraction of John's words.  Herod clearly needed discernment, where he might have been able to distinguish between what God was calling him to and the resistance of his flesh (not just his adulterous union but his enthrallment to self will).

Each of us has these moments where we face different possible paths of action and we are forced to choose among them.  We often choose on the basis of what will cause us the least trouble, make the fewer waves, or allow us to seem brighter or more confident instead of looking to what God is asking of us.  We do not face the decision of killing a prisoner or even merely freeing him, certainly not in the literal sense, but we can choose how generous we will be in giving life to others or freeing them from some sort of bondage (such as poverty, loneliness, or low self-esteem).

God is constantly offering us such chances to see the world through his eyes, to love the world and to choose our own selves in the heart of his Son, and to yield to the Spirit's urging, but to do so we need to spend time consulting God in prayer, becoming familiar with God's words and ways, so that when we are suddenly confronted with a critical choice we are clear as to what is at stake and what we have made our fundamental preference.

This preference is important, since it is not only important choices like the one that Herod faced which call it into action.  Dedication to God's will and a readiness to listen to God's Spirit need to be operative at all times.