That can be interpreted also to work it through, not to earn it but to mature in it.
And THAT interpretation does not conflict with the eternal security promised to believers being sealed by the Holy Spirit.
So tell me, if believers are sealed by the Holy Spirit, what exactly does that mean if not to be kept from *losing* their salvation?
What then, is the point of sealing anyway?
And why call the deposit of the Holy Spirit in the life of the believer a guarantee of his inheritance until he takes possession of it, if it is not guaranteed because the person may do something to lose it? How is that being sealed?
“work out your salvation with fear and trembling” is obvious, straightforward, easily understood and requires no further “interpretations”. (the meaning of is, is)