“Be sober, be vigilant; because your adversary the devil, as a roaring lion, walketh about, seeking whom he may devour:”
1 Peter 5:8

He makes it clear why you should be sober and vigilant, he says if you’re not, you could be devoured. Jesus said:
“The thief cometh not, but for to steal, and to kill, and to destroy: I am come that they might have life, and that they might have it more abundantly.” John 10:10
Satan seeks, he looks for opportunities to cause mayhem and destruction in the life of others, and the word of God is saying those who get distracted or carried away with the spirit of the world would be devoured. Look at what Jesus said:
“When the unclean spirit is gone out of a man, he walketh through dry places, seeking rest; and finding none, he saith, I will return unto my house whence I came out. And when he cometh, he findeth it swept and garnished. Then goeth he, and taketh to him seven other spirits more wicked than himself; and they enter in, and dwell there: and the last state of that man is worse than the first.” Luke 11:24-26
He makes it clear that you have an adversary, and it’s not because you did something wrong. This adversary is actively looking for opportunities to destroy you and he might get them once you stop being vigilant and sober, but that is not how your life’s story should go, when you are vigilant, you would notice his inspirations- inspiring events or people to actively work against God’s plan for your life-and resist him like Jesus did:
“Then Peter took him, and began to rebuke him, saying, Be it far from thee, Lord: this shall not be unto thee. But he turned, and said unto Peter, Get thee behind me, Satan: thou art an offence unto me: for thou savourest not the things that be of God, but those that be of men.” Matthew 16:22-23