1 Peter 5:8
Be sober, be vigilant; because your adversary the devil, as a roaring lion, walketh about, seeking whom he may devour:
There is no reason for us to go around giving God only so much of ourselves. Why would we only give so much of our selves when he give us all of him.
The enemy of God walks around search for searching for those who are half-stepping. He looks at them like a lion ready to to devour them first. He does not play fair. He does not have an honor code. He honors nothing or no one. Those who walk half heartily are those who are not vigilant. They are walking with their eyes closed. They are walking with their minds closed off to the dangers that are ever present.
Much like the jungle, if we are not aware of the dangers we will become the prey of all the unseen dangers hiding in the camouflage of their natural habitat. The prey are the prey because they are unaware.
There is nothing sillier that someone walking in a place of danger without a care in the world. many of them are going to blame God for not protecting them through the unseen dangers, but he will show you where he warned you not to go into certain places and situations. He will show you where he warned you beforehand of dangers ahead. But we walked according to the dictates of our flesh, and the lust of our flesh, and the pride of life, into those things that devoured us.
Be watchful. Be careful. Keep your eyes and ears open to all things. Be aware that the enemy wants to ambush you and eat you alive.
