Are you so foolish and senseless? Having begun [your new life by faith] with the Spirit, are you now being perfected and reaching spiritual maturity by the flesh [that is, by your own works and efforts to keep the Law]? - Galatians 3:3 (AMP)
I often like to believe that I am not that bad of a person.
I sometimes think, "Wow! I've been so good recently! I am working and taking care of my husband and reaching people for God!" But the funny thing is, as soon as I have these thoughts, I do something really stupid. I usually end up fighting with my husband or my family, thinking horrible thoughts about others, judging people, having road rage, or just getting into some kind of unnecessary trouble because of my attitude.
That's because I am not actually good. The Bible tells us that none of us are. Yes, we sometimes do good things - We show compassion, love, or care for others - but unfortunately, none of us are truly good at being good. We fall short of the term "good" all the time when we judge, condemn, hurt, or fight with other people. When we do these things, we are also hurting God. See Matthew 25:41-46:
“Then he will say to those on his left, ‘Depart from me, you who are cursed, into the eternal fire prepared for the devil and his angels. For I was hungry and you gave me nothing to eat, I was thirsty and you gave me nothing to drink, I was a stranger and you did not invite me in, I needed clothes and you did not clothe me, I was sick and in prison and you did not look after me.’ They also will answer, ‘Lord, when did we see you hungry or thirsty or a stranger or needing clothes or sick or in prison, and did not help you?’ He will reply, ‘Truly I tell you, whatever you did not do for one of the least of these, you did not do for me.’ Then they will go away to eternal punishment, but the righteous to eternal life.” (NIV)
From these verses in Matthew, we can see that God cares a lot about how we treat other people. This means that every time we fight with someone on social media, display fits of road rage, inwardly condemn someone, or avoid a person because of the way they look, we aren't doing anything to help ourselves, that person, or God's kingdom. We are being the opposite of good - we are being bad.
The only way we can really learn to be good is to have God's Spirit inside of us. The Spirit teaches us how to be good more consistently. The end result is spiritual maturity. Though our original nature will always try to pull us back towards sin, the Spirit constantly convicts us and pulls us forward. In this way, the Spirit teaches us how to reach spiritual maturity.
This is why we need to stop trying to be good all by ourselves. Paul says in Galatians 3:3, that it is impossible to be good by ourselves. We are unable to reach spiritual maturity, even by following the Old Testament Law. The only way we can reach spiritual maturity is by accepting Jesus and the Holy Spirit.
Are you so foolish and senseless? Having begun [your new life by faith] with the Sp