Many natural things are prickly. The thorns are the natural defense for many roses, orange trees, and weeds. Grabbing hold of a prickly stem results in one's letting it go and coming up with another plan. The "pricks" are the plant's protection.
God uses the "pricks" of uncomfortable circumstances in our lives to change our direction. He did this in Paul's life, as the unsaved but religious man traveled on the Damascus road.
Acts 9:5 "And he said, Who art thou, Lord? And the Lord said, I am Jesus whom thou persecutest: it is hard for thee to kick against the pricks."
Paul had spent of much of his life trying to serve God his own way. Unfortunately, he did not detect, nor heed, the "pricks" God sent in His life to turn him in the right direction that God desired.
"Pricks" that Saul ignored:
"Pricked" ears - When Paul heard the preachers of the Gospel, he did all he could to stifle their preaching. Instead of pricking his conscience so he could change his wrong path, it angered him and encouraged him to do more to silence Christians.
He even held the coats of those that stoned the deacon, Stephen. While he was standing there he probably heard the Word of God, as at other times, when he was around Christians. Still he held to his own religion, even when the people of God preached and warned against it.
"Pricked eyes" - Undoubtedly, he saw Christianity in action. He saw families split, people die, and heartache inflicted, but still the Christians would not waiver in their obedience to God's commands. In all the trouble he instigated against Christians, he saw that that they had a peace that he surely did not understand. He was like his name-sake, King Saul, who persecuted righteous David.
"Pricks" that others ignore:
Pricked by circumstances: Hard times, sickness, failures, testings, aggravating situations, disasters, etc. are many times meant to draw us closer to God and to cause us to trust him more. Instead, folks many times grow farther from the source of strength they need during those hard times. They do not examine themselves and what they are doing in God's eyes, and do not get the message that God is trying to send them through their trials.
Pricked ears: Perhaps, God sent a godly mother, grandmother, neighbor, friend, or Sunday school teacher to us, or let us hear a preacher on TV; but still His invitation was ignored. People often do not "hear" what God is trying to tell them.
Pricked eyes: We've seen bits of the Word of God in tracts and good Christian testimonies, yet we ignore His words and the godly examples allowed to cross our path. Too often we do not heed God's "pricks" to our heart.
When examining your life, do you see any obstacles God may have put in the way to change your direction? Is it possible you are fighting or ignoring the obstacles God has allowed to be placed in your life to get you to turn in the direction He desires? Are the "pricks" allowed in your life not changing your direction to where God wants you? If so, what will you do next?