What's striking about Salvation in the Bible is that it is always compared or likened to other things that happen at a single moment in time and are easy.
For example, some metaphors for Salvation in God's Word are:
None of the things above require devotion or service, and none of them take a lifetime. That's because faith, which is the sole basis for Salvation (Romans 4:5), happens in a moment, and is easy.
In fact, faith is the antithesis of works (Ephesians 2:8-9, Romans 11:6), because you are putting your trust in someone else's work entirely. That's why when God gives a metaphor for Salvation, He gives the above.
In contrast, every single false religion on this planet teaches that getting to Heaven is a tremendous undertaking, and requires diligent obedience to certain rules, self-sacrifice, and keeping up both until your dying breath.
If so, these metaphors are utterly inappropriate, as they give false impressions. I'm told I have to eat bread once and I'll never hunger again (John 6:35, 6:50-51, 6:58), when in reality, I have to make the bread myself, and eat of it continually for the rest of my life, lest I die of starvation.
I'm told I have to drink water once, and I'll never thirst (John 4:10-14), when in reality, I have to come to the well and keep drinking for my entire life, lest I die of thirst. So on and so forth - all of these metaphors are nullified if in fact they aren't referring to something easy, that takes place in a moment.
The world desperately wants to pull themselves up by their bootstraps in order to get to Heaven, even though God has made it clear that He does not accept works as the basis for atonement (Ephesians 2:8-9), which is why all of His metaphors reject that notion. Only the payment of Jesus Christ is accepted as the basis for atonement (Hebrews 9:22 w/ Hebrews 9:12), which is what all of these metaphors point to.
These metaphors all bear witness to the fact that Eternal Life is offered "freely" (Romans 3:24, Revelation 22:17).
Most of the world rejects this fact, in favor of clinging to some invented standard of holiness that cannot pay for their sins, nor justify them before God. In doing so, they nullify these metaphors, and reject that they mean what they plainly convey.