Conditional salvation is a form of legalism.
In contracts, legal, there are 2 parties. There are terms and conditions stipulated in the contract, and penalties associated with non performance of said conditions. Conditional salvation is a similar effort.
Contract law doesn't apply to God in Christ, and can't. It's a unilateral conveyance, meaning it only comes from one direction. It's not a 2 way contract.
In the Gospel, the precursor condition to receipt is the inability of the other party to perform. Grace is unmerited favor. Mercy is a one way grant, given the inability of the recipient to perform.
This type of one way extension is seen here, for example. The pharisee approached God in a legalistic manner, thinking, quite entirely falsely, that by his actions and abilities to perform, he was justified. He wasn't.
Luke 18:
9 And he spake this parable unto certain
which trusted in themselves that they were righteous, and despised others:
10 Two men went up into the temple to pray; the one a Pharisee, and the other a publican.
11 The Pharisee stood and prayed thus with himself, God, I thank thee, that I am not as other men are, extortioners, unjust, adulterers, or even as this publican.
12 I fast twice in the week, I give tithes of all that I possess.
13 And the publican, standing afar off, would not lift up so much as his eyes unto heaven, but smote upon his breast, saying,
God be merciful to me a sinner.
14
I tell you, this man went down to his house justified rather than the other: for every one that exalteth himself shall be abased; and he that humbleth himself shall be exalted.
The marks of the pharisee are always similar. They justify themselves, and they despise others for their lack of performances, compared to their own. And they lie to Gods Face about the fact that they are sinners.
Thusly, they are turned to hypocrisy by the Hand of God, being against them for their dishonesty.
The receipt of Divine Mercy and unmerited favor aka Grace, is predicated on "needs," because we are in fact sinners. It's a one way street, not a 2 way contract. No one in truth can say before our Maker, truthfully, that they are not sinners, regardless of any of what they might do performance wise.
Jesus shows this same thing again, here, showing the "correct" mindset of His servants:
Luke 17:10
So likewise ye,
when ye shall have done all those things which are commanded you, say,
We are unprofitable servants: we have done that which was our duty to do.
Where is that voice amongst all who "conditionally" justify themselves? You'll never hear it because it is an offense to their pride. Every now and then you might hear one squeak out that they are sinners, after much prompting to be honest, that is. And then, invariably, they will quickly resort to whatever theological performance rituals/contract/conditional performance quotients that they use to avoid being judged for being sinners. In effect saying, yeah, I'm a sinner, but I did this to avoid being a sinner.
Uh, no, you didn't. Such are just playing legal games with The Word,
no different than the pharisee given as an example, by Jesus.