One does not lose salvation (being sealed by the Holy Spirit for salvation Eph 1:13) by sinning, one loses their salvation by giving themselves over to a life of sin without repentance. Choosing a life of sin wilfully...
Heb 10:26 For if we sin willfully after we have received the knowledge of the truth, there no longer remains a sacrifice for sins,
Heb 10:27 but a certain fearful expectation of judgment, and fiery indignation which will devour the adversaries.
Heb 10:28 Anyone who has rejected Moses' law dies without mercy on the testimony of two or three witnesses.
Heb 10:29 Of how much worse punishment, do you suppose, will he be thought worthy who has trampled the Son of God underfoot, counted the blood of the covenant by which he was sanctified a common thing, and insulted the Spirit of grace?