Satan's infiltration into the modern-day church through worldliness and doctrinal errors should deeply concern all true believers as to the compromised standing of the church in becoming so entangled with the world and not bearing true salt and light.
The true church represents a called out body of believers, and if the church has been called from something, it has also been called to something that through holy living, God may be glorified through her actions.
God's decree is infallible and represents His sovereign will and purpose in salvation. It was "foreordained before the foundation of the world" (1 Peter 1:20) where God the Father made a covenant of redemption with the Son, and in fulfilling this agreement at Calvary, Christ has purchased the Grace that is applied to all believers by the Spirit, who now stand eternally justified and sealed in the Spirit.
While a believer has everlasting joy and assurance in Christ, the pull of the flesh against the Spirit is something that will follow all the days of his life. This dilemma, that sin, like a foreign intruder, will always try to lure itself back into a believer's soul. Believers are thereby at peace with God, but they are never at peace with sin for which the Apostle states that obedience to the law boils down to one command, "to love one another: for he that loveth another hath fullled the law" (Romans 13:8).
Dening exactly who God's covenant people are is also considered as Satan has attempted to doctrinally divide believers from both the Old and New Testament. Election according to Grace is the great link from the remnant that was saved throughout the Jewish age of the church to Gentile believers of today. It is all of Grace