John Gill Commentary Ezekiel 33:13

"When I say to the righteous, that he shall surely live; if he trust to his righteousness, and commit iniquity, none of his righteous deeds shall be remembered; but in his iniquity that he hath committed, therein shall he die." — Ezekiel 33:13 (ASV)

When I shall say to the righteous, that he shall surely live ,
&c.] A happy life, here and hereafter; an eternal life, and not die the second death: this must be understood, should he appear a truly righteous person; one that does not trust to his own righteousness, but to the righteousness of Christ, and lives by faith on that; looking for the hope of righteousness through it, and behaving agreeably to his character:

but if he trust to his own righteousness, and commit iniquity ;
as he will by trusting to it; if he trusts to it for acceptance with God, and justification in his sight, and thinks himself proof against all temptation to sin on account of it; and that he has righteousness enough to make amends for sins committed, or for other sins he may commit; and which he may venture upon through this false notion, and so be led on to an open course of sinning, and series of committing iniquity:

all his righteousness shall not be remembered ;
God will take no notice of it; it shall be of no avail to justify him from sin, and secure him from wrath; it will be as if it never had been: but for his iniquity that he has committed, he shall die for it ;
an eternal death, which is the just wages of sin; from which a man's own righteousness can never deliver him, though the righteousness of Christ does deliver from it; see (Proverbs 10:2) (11:4) .