You can never lose your salvation.

Does this sound like a strong salvation or a weak one? Do you think the Lord Jesus is big enough and strong enough to secure your salvation for all time? When scripture says that we have been placed, by God, into God (1 John 4:15), do you believe it? If you do believe, would not "being in God" be the absolute safest and most secure place in the universe? He claims that no one can snatch us out of His, or the Father's, hands (John 10:28-29). Is this salvation secure enough for you? Is there anything more that you can do to help God keep you saved? Is there any boast you might claim of how you added anything to your own salvation?
For those who may doubt their salvation from time to time, I want to make sure that we understand exactly who it is that now lives within us. Scripture declares that Jesus, who spoke all things into being (John 1:1-5), dwells in us as our salvation. Most of us, while carefully listening to a sermon or Bible study on this spiritual truth, will readily nod in agreement. Yet in our daily life as Christians, we often act as though this same Jesus is a ninety-pound weakling, an easy target for any bullying circumstance that comes along. If you ever question or doubt whether you are saved, your idea of Jesus is far too small. Let’s see whether Jesus is big enough for the job of keeping you saved.
We'll start with the fact that He is God. You know the God I am speaking of don’t you? The How-Great-Thou-Art Almighty God? The Creator-God who spoke, “Let there be light” and the sun, moon, and billions of stars sprang into existence in uncountable galaxies across an immeasurable universe (Genesis 1:14-18)? He is the “Word” of God that existed from the beginning, who is the source of everything that exists (John 1:1-3). He is the same God who maintains this creation from moment to moment by His power (Colossians 1:17). If He were to remove His breath from the earth, all living things would perish (Job 34:14-15). For from Him and through Him and to Him are all things (Romans 11:36).
He is the God who laid the foundation of the earth, and set the boundaries of the waters; who lifts His voice to the clouds and fathers the rain (Job 38:4, 10-11, 34, 28). It is He who set the sun in its place and the moon for the seasons (Psalm 104:19). He is the one who fixed the storehouses of snow and rain, and commanded that they come down and water the earth and make it produce, to furnish seed for the sower and bread to the eater (Job 38:22; Isaiah 55:10).
He is the source of every good thing and every perfect gift; the Father of lights, with whom there is no variation or shifting shadow (James 1:17; see also Acts 17:24-25). As the Amplified Bible states, “Now to Him Who, by (in consequence of) the [action of His] power that is at work within us, is able to [carry out His purpose and] do super-abundantly, far over and above all that we [dare] ask or think [infinitely beyond our highest prayers, desires, thoughts, hopes, or dreams]” (Ephesians 3:20, AMP). The world is His (Psalm 50:12).
Yes, I am talking about that God. The only true God (John 17:3). Shall I go on about His infinite wisdom, holiness, righteousness, and sovereignty? Or can we safely acknowledge the fact that God is not small? That He is big enough to save you and keep you saved? The only thing “small” is our thinking of Him!
This is the God who is our salvation. It is a salvation evidenced by the attraction we have for Him, an attraction that He quickens in our hearts as part of His continual working in us. It is a salvation confirmed by our belief, which He has given us, in contrast to the world around us that does not believe.
Ask yourself: “What can I possibly do to add anything to this perfect salvation?” By God's sovereign mercy, He has chosen to grant us salvation fully accomplished by God Himself. We have nothing to boast of in ourselves before Him (1 Corinthians 1:29). Let him who boasts, boast in the Lord (1 Corinthians 1:31)!
From the book, "A Different Place," The peace and freedom that comes from knowing: God has done it all—He is all we need, pages 65-67.