These are the things that I know.
I am a sinner. The prophet Isaiah said that all of his righteousness was as filthy rags - if his were rags, what must mine be? There are NONE righteous not even one! There is nothing at all that I can DO to earn getting into heaven.
Read this, and then read it again - I cling to it.
"...even as he chose us in him before the foundation of the world, that we should be holy and blameless before him. In love he predestined us> for adoption through Jesus Christ, according to the purpose of his will, to the praise of his glorious grace, with which he has blessed us in the Beloved. In him we have redemption through his blood, the forgiveness of our trespasses, according to the riches of his grace, which he lavished upon us, in all wisdom and insight making known to us the mystery of his will, according to his purpose, which he set forth in Christ as a plan for the fullness of time, to unite all things in him, things in heaven and things on earth.
He chose us! Even before the earth was created, IN LOVE he chose us.
He knew all of the bad things I would ever do, all the dishonor I would bring Him - and He loved me anyway!
Christ died for me! ME! That is amazing and humbling. It is nothing of myself, the glory is God's alone.
The Reformers say, "Soli Deo Gloria" - to the glory of God alone. Anything or anyone that gets between me and Christ's once and for all sacrifice on the cross, takes away from God's glory.
If I trust in Christ alone, for His grace alone, I belong to Him.
John 10 says that we are given to Christ by the Father. Those who believe are the Father's gift to Christ!
This is present tense - we can be sure of our salvation.
There is only one way to heaven. Jesus said, "I am the way, the truth, and the light."
Salvation is apart from the Law (things that we DO), through faith I am justified by His grace as a gift. I cannot earn it and if I try, I will fail miserably.
If you have this faith alone, in Christ alone, you already have His grace as a gift. You don't need all of the external "stuff" - all you need is the grace of Christ.
You can have assurance of your future...1 John 5:13 I write these things to you who believe in the name of the Son of God that you may know that you have eternal life.
I know that there are those who add requirements and teaches that you cannot be sure - but the Bible says that grace is a gift, not something we earn - and that we who believe in the name of the Son of God - we may KNOW!
It is in Christ (alone) by grace (alone) through faith (alone) that we know we are His. There is no other way.