How do you know?

I encounter this question a lot in various contexts.

Often it is asked in regard to God's existence - how do you know there is a God. Well there are loads of reasons, many of which have been written about on this site (see here for example), but at a more fundamental level, it is only the existence of the God of Scripture that actually makes sense out of the concept of knowing anything. God is not merely the conclusion of an argument, but He actually needs to be the starting point, or knowledge isn't really possible. I know that's all a bit vague for some, but I stand by it as being true. If we do not believe in a sovereign, rational, logical, moral God (and only the Trinue God of the Bible fulfils that description) then we cannot justify any of our beliefs without relying on immaterial concepts which cannot be accounted for in a worldview that denies such a God.

But what I want to mention is that many people who accept the existence of God deny that it is possible to know that one is saved and going to heaven. I want to give three reasons why I know.

1. The work of Christ - I know I am saved because I am not depending on myself but on the sacrifice of Christ on the cross. It is not the case that I think I'm good enough - I know that I'm not good enough, but I am relying on the fact that the Lord Jesus Christ took the punishment I deserved and paid the price I owed. So because I am depending on a Saviour who cannot fail I have no reason to doubt my security (Romans 5 v 9; Hebrews 7 v 25). It's not pride.
2. The word of God - I know I am saved because God has promised that those who put their trust in the Lord Jesus for salvation will never perish (John 3 v 16; 5 v 24). If someone makes you a promise it is not a mark of humility to doubt it, it only says you don't think the person making the promise is trustworthy. God is the God who cannot lie, and He says it is impossible for a person who has trusted Christ to ever be lost (John 10 v 28; 1 John 5 v 12-13). It's not presumption.
3. The witness of the Spirit - I know I am saved because eternal life is not something I have to wait for and get in the future. Eternal life is something a person gets upon receiving Christ as Saviour (e.g. 1 John 5 v 12; John 3 v 36; 5 v 24). Upon trusting Christ for salvation, the Spirit of God dwells within the believer, giving new life and new desires (e.g. 1 John 4 v 13; Romans 8 v 9). It's not premature.

So the Trinity gives the believer solid ground for faith to rest on. I hope you'll rest on it, and enter into the certainty of God's salvation.