We know that anyone born of God does not continue to sin; the One who was born of God keeps them safe, and the evil one cannot harm them.
1 John 5:18
When we become a child of God, we’re expected to put away the old person for we’re altogether a new creation (Ephesians 4:22-24). Our thoughts should no longer be ours. Our old ways should no longer linger. Our hearts should no longer be deceitful. If we really and truly believe and belong to God, then why do we keep sinning? Some of us wilfully sin, but call it a “mistake”, a “flaw”, an “imperfection”! We can dress it up beautifully and call it whatever we want, but a sin is a sin.
We live in a world where temptation is always on the rise. We foolishly think that we have everything under control without relying on God only to be dragged back to our youthful lusts which God tells us to flee (2 Timothy 2:22). We all sin (Romans 3:23), but when we come to Christ by faith, He cleanses us of our sin thus we’re born again (John 3:3). God doesn’t make us righteous, He declares us righteous (Romans 5:1) for we’re still in the flesh and there’s always going to be a constant battle between the flesh and the spirit. You’re going to lose some, you’re going to win some, but if we’re fully surrendered to the control of the Holy Spirit, we’re going to win those battles constantly (Galatians 5:16-17).
Jesus showed us the way out. When He was tempted, He “offered up prayers and supplications with fervent cries and tears to the one who could save him from death” (Hebrews 5:7). We have to continually submit to God allowing the Holy Spirit to work in us for the Holy Spirit is given to those who obey Him (Acts 5:32) and He works in us to transform us into the image of Christ (Romans 8:29).
As long as you’re fighting and resisting the lust, you’re not sinning. It’s going to be a continuous battle for the Spirit of God and the flesh are at war.
In Matthew 5:48, Jesus wants us to strive for perfection as it is God’s standard for us. However, Jesus knew that in reality, we would fail that standard for we’re still in the flesh hence the reason why He died for our sins (Romans 5:8).