I have written before and received a helpful answer, so I hope that you have some advice for me in this issue. I'm an 18-year-old who has been a Christian since I was 4. However, I have recently discovered the true everyday Christian life (not just Bible reading every day and prayer, but an actual walk with Christ in which I try to please him in everything). Recently, I have noticed that in my free time, my thoughts tend to wander in places I don't want them to go. Some are downright sinful but most are just not edifying and Christ-like. I was hoping you could give me some hints about how to keep my thoughts pure and edifying, and, more importantly, how to replace the ones that aren't righteous with Christ and his thoughts.
One reason Jesus said that people must become like children to enter the kingdom is because they are innocent in regards to sin; thus, they are humble in obeying the Lord (Matthew 18:2-4). "Brethren, do not be children in your thinking; yet in evil be infants, but in your thinking be mature" (I Corinthians 14:20). Children have no knowledge of good and evil (Deuteronomy 1:39). But that changes as they grow up. Somewhere during the teenage years they become aware of sin and their personal responsibility.
And it is also during the teenage years that we become aware of sex, so not only are we battling sin we are also being attacked from an unfamiliar direction. We have not yet developed experience in dealing with sexual temptations. Sadly, it is unexpected struggle that often causes people who commit to Christ early in life to fall away in young adulthood. It is easy to be good when there are few temptations, so people get complacent and are unprepared when the real battle strikes.
Generally, I would argue that a child of four is not yet ready to become a Christian. Because of their innocence, they are not yet guilty of sin. But one of the requirements for becoming a Christian is an awareness of your personal sins and a turning away (repentance) from those sins (Acts 2:38; 3:19). I invite you to take a look at How to Become a Christian and make sure that you are on the right path.
Idleness means you have no particular goal in mind and thus you can be easily distracted. For this reason, all Christians are commanded to work. "For even when we were with you, we commanded you this: If anyone will not work, neither shall he eat. For we hear that there are some who walk among you in a disorderly manner, not working at all, but are busybodies. Now those who are such we command and exhort through our Lord Jesus Christ that they work in quietness and eat their own bread" (II Thessalonians 3:10-12). Therefore, one answer is to minimize the time you have nothing in particular to do.
Another problem is that people will approach being a Christian as solely about not sinning. "Now when the unclean spirit goes out of a man, it passes through waterless places seeking rest, and does not find it. Then it says, 'I will return to my house from which I came'; and when it comes, it finds it unoccupied, swept, and put in order. Then it goes and takes along with it seven other spirits more wicked than itself, and they go in and live there; and the last state of that man becomes worse than the first. That is the way it will also be with this evil generation" (Matthew 12:42-45). The problem that Jesus illustrated is that when we just get rid of sins from our lives, we leave a vacuum, just waiting to be filled. Thus, the answer is to fill your life and your mind with so much good that there isn't much room for sin to enter. "But put on the Lord Jesus Christ, and make no provision for the flesh in regard to its lusts" (Romans 13:14). That really means learning your Bible and putting it into application in every faucet of your life. "Therefore, putting aside all filthiness and all that remains of wickedness, in humility receive the word implanted, which is able to save your souls. But prove yourselves doers of the word, and not merely hearers who delude themselves. For if anyone is a hearer of the word and not a doer, he is like a man who looks at his natural face in a mirror; for once he has looked at himself and gone away, he has immediately forgotten what kind of person he was. But one who looks intently at the perfect law, the law of liberty, and abides by it, not having become a forgetful hearer but an effectual doer, this man will be blessed in what he does" (James 1:21-25).
No matter how well we battle sin, the simple fact is that everyone of us will at times slip. It is not an excuse for sin, but a reality check. "If we say that we have no sin, we are deceiving ourselves and the truth is not in us. If we confess our sins, He is faithful and righteous to forgive us our sins and to cleanse us from all unrighteousness. If we say that we have not sinned, we make Him a liar and His word is not in us. My little children, I am writing these things to you so that you may not sin. And if anyone sins, we have an Advocate with the Father, Jesus Christ the righteous" (I John 1:8-2:1).
Thank you for your advice on my thoughts. Most of them were not sinful, they just weren't edifying and I'm looking for ways to replace them with better ones. I agree that when I'm doing things (such as schoolwork) I tend to focus on those things and not have a wandering mind. I guess that some of my problem stems from the fact that I have a very active mind.