Isaiah 10:5-12

Isaiah 10:7
But this is not what he intends, this is not what he has in mind; his purpose is to destroy, to put an end to many nations. 

God sends an Assyrian against nations to punish them for being godless. As we read the passage we see that the Assyrian has his own intentions despite what he was sent out for in the first place. Being born as sinners, we often make up our own intentions for our own purposes. We forget that God has control and is sovereign over us. He bought us with the blood of Christ His Son. God being the ruler of our lives has a plan already set out for us from the start. Like a child obeying their parents, we too must obey the Lord and His good purpose for us.

The passage continues on and we read of the Assyrian boasting about his victories and how he has the ability to seize any nations without having to destroy them as what God has asked him to do. His arrogance clearly shown leads to the Assyrian's own punishment.

Isaiah 10:12
When the lord has finished all his work against Mount Zion and Jerusalem, he will say, "I will punish the king of Assyria for the willful pride of his heart and the haughty look in his eyes. 

Do not become prideful and arrogant for your successes, abilities, and talents as they originate from the Lord   as blessings and gifts for us.