1) Eternal Salvation: God’s forgiveness of all our sins, Heaven irrevocably guaranteed, eternal life, eternal security, everlasting connection with a loving God, and a new, holy, loving, righteous self, in Christ and also indwelled by Christ, are the free and loving gifts of Jesus.
We receive this free gift of God’s love in the moment of belief in Jesus, when we believe in the Gospel of Christ. The Gospel message, the Good News, is that Jesus, who is God and man, shed His blood and died on the cross for all of our sins (past, present, and future) according to the Scriptures, was buried, and was resurrected from the dead on the third day according to the Scriptures.
2) Practical Sanctification and Communion with God: living daily, in this life, by faith in the perfect and righteous person we have been made in Christ, as children of God our Heavenly Father, indwelled by God’s Holy Spirit, having died with Christ and having been raised to new life with Christ. This perfect, holy, and righteous new self is indwelled by Christ. We do not not believe in ourselves, but in Christ who Himself ~is~ the righteousness of those who believe in Him, by His grace.
In Practical Sanctification, in our present daily life, believers in Jesus, by faith, are ~living by faith in the new holy person we are, in Christ~ which is in union and complete dependence on Christ the Vine. Believers were made into holy persons in Christ by God in the very moment we were saved through faith in Jesus. When we live by this spiritual reality in Christ, we live the Christian life of communion and sanctification, in God.
In the natural sinful nature of the flesh, we are potentially as sinful, evil, and wretched as we ever were.
By God’s grace, we can daily live by faith in this new life in Christ.
I believe that Salvation in Christ and Practical Sanctification/Communion with God are the two most important truths of Christianity that should be focused on and made preeminent in order for people to have eternal salvation; and also for them to have true spiritual growth in the grace of Jesus, who loved us and gave Himself for us, to forgive us our sins and deliver us from our sin and evil and estrangement from God, to His goodness and love.
In one sense (positional justification), believers in Christ already ~are~ what God wants us to be, and we are seated in the heavenly realms with God. In the rest of our earthly lives, we have the opportunity to live out of our status as children of God, following His indwelling Spirit, by our spirits. When we do this, we become sanctified in practical reality, we live in fellowship with God, and we become powerful in doing the will of God, knowing Him deeply.
Believing God’s many promises, and loving God and others and yourself, and obeying God’s will in His Word, and as perceived in the conscience and intuition of your spirit, makes zero difference to the salvation of those who have believed in Christ as Savior.
But these things make a huge difference to your rewards in Heaven, to being practically pleasing to Your heavenly Father who loves you, to living out your holy and resurrected identity in Christ, to being and acting loving to others and to yourself, to experiencing close fellowship and communion and love and joy and peace between God’s Holy Spirit and your spirit, and to practical sanctification by grace through faith in Christ.