In 1 Timothy 4:11, Paul instructs Timothy, "Keep a close watch on yourself and on the teaching. Persist in this, for by so doing you will save both yourself and your hearers." (ESV)
Paul desired that his young protege would be careful about his manner of life and the content of his beliefs. And, as God's people, we must all be aware of how we are living and what we believe.
Our Manner of Life
What does our manner of life say about us? Whom does it say we serve? We all know the phrase, "Actions speak louder than words," and perhaps that is more true (if that is possible!) for the Christian. For those who claim the name of Christ, and yet act in a manner contradictory of the Lord Jesus, they bring great shame on the Lord and confuse people who are not His followers. It can also hinder people's own walk with God, or lack thereof.
Christians have enjoyed a period of cultural acceptance up until very recently. Now, however, society, in general, lies in opposition to almost all Christian values. The after effects of this, however, are more detrimental than society's rejection. Consider David Kinnaman's and Gabe Lyons conclusion, "The hypocritical perception is most acute not when a religion is on the fringes of society, but when it has because a dominant part of the culture." (Kinnaman and Lyons, UnChristian, 43) For centuries Christianity has enjoyed a certain prestige in American society. However, that is already shifting, rapidly and increasingly. Now, more than ever, Christians need to "keep a close watch" on their lives. Those who pretend to be in Christ's sheepfold are leaving in the droves, and Christ's true followers must live as their Lord did. They must pay special attention to their lives.
One practical way in which we can do this is to incorporate a time of self-examination every day. I suggest the 10 Commandments, due to their consistency in Scripture as well as their ease in reading and comprehension. Regularly ask yourself, "Am I following the 10 Commandments? How does my life differ from what God has taught?" Questions like these will help you keep a close guard of your life.
Our Matter of Beliefs
In 2018, Ligonier conducted a study on what people believed (you can find the study, including the research methodologies, here: https://www.ligonier.org/blog/state-theology-what-do-people-really-believe-2018/). One of the results was the distinct declaration that people today do not believe what the Scriptures teach, Christian and otherwise alike. Some of the questions are basic aspects of the faith, and it is shocking to see.
However, before we criticize others, are we engaged in serious study of our Faith? Do we regularly search the Scriptures and see what they teach? I am certainly not advocating for people to sit down and read systematic theology books (though that would be helpful!). However, when we cannot agree on what the Scriptures teach about the exclusivity of Christ, are we keeping watch of our doctrinal beliefs?
What we believe affects how we live, which in turn affects what we believe. What are some ways you can watch your doctrine? I find Statements of Faith to be helpful, particularly in the context of your church. What does your church believe? Study their Statements of Faith. You can also check our declarations such as the Baptist Faith and Message 2000 (here: http://www.sbc.net/bfm2000/bfm2000.asp). It is an excellent summary of beliefs, which also include references to Scripture.
Another helpful tool are systematic theologies. Now, I would caution you on which ones you choose. First, they can be extremely academic. While there is a need for them, it may not produce the same fervor for understanding God more. Another aspect to be aware of is the beliefs. There are systematic theologies that espouse heresies. Finally, take care with how you approach your study. It can be an exercise in gaining knowledge, but unless it helps you know and love God and your neighbors more, it is fruitless.
So, brothers and sisters, pay attention to your life and your beliefs. And to God be the glory!