Preemptive teshuvah over thoughts saves from sin

בפסוק יעזוב רשע דרכו ואיש און מחשבותיו.

On the posuk, "Let the wicked one forsake his way, and the man of iniquity his thoughts" (Yeshayahu 55:7).

The Sefas Emes examines why the posuk distinguishes between the "rasha" who must abandon his "way" and the "ish aven" who must abandon his "thoughts."

דאיתא במשנה האומר אחטא ואשוב אין מספיקין בידו לעשות תשובה.

For it is stated in the Mishnah: one who says "I will sin and then do teshuvah" — they do not give him the opportunity to do teshuvah.

The Mishnah (Yoma) teaches that one who plans to sin while relying on teshuvah afterward is denied Heavenly help to repent.

והטעם כיון שבתשובה עצמו חטא ועי"ז דרך התשובה נתרחק ממנו.

And the reason is that he has sinned in the very matter of teshuvah itself, and through this the path of teshuvah is distanced from him.

By exploiting teshuvah as a license to sin, he corrupts teshuvah itself; the avenue of repentance therefore moves away from him.

ומדה טובה מרובה וא"כ מי שחוטא בשגגה ובמחשבות זרות שסופן להביא לזדונות ועבירות בפועל.

And the measure of good is greater; if so, one who sins inadvertently (b'shogeg) and with foreign thoughts (machshavos zaros) that will ultimately lead to willful sins and actual transgressions —

Since the measure of reward always exceeds the measure of punishment, the reverse case must work even more powerfully: consider one whose lapses are only unintentional or in stray thoughts that could eventually lead to deliberate sin.

ואם מתעורר בתשובה על כל אלה.

and if he arouses himself in teshuvah over all these,

If such a person does teshuvah already at the stage of these slight, inadvertent stirrings,

כדי שלא לבוא לעבירות.

in order not to come to actual transgressions —

doing so precisely so that he will never reach actual sin,

וז"ש איש און מחשבותיו שעדיין לא חטא וע"י פחד החטא שב מקודם.

and this is the meaning of "the man of iniquity his thoughts" — that he has not yet sinned, and out of fear of sin he repents beforehand.

The "ish aven" of the posuk is one who forsakes even his thoughts, repenting in advance out of yiras cheit before any actual sin has occurred.

מצילין אותו מן החטא.

they save him from the sin.

Just as the schemer is denied the chance to repent, this person — who repents preemptively — is given Heavenly help and rescued from sin entirely.

שהרי החטא גרם לו התשובה ותיקון מחשבותיו לכן נתרחק מן החטא:

For the (potential) sin caused him to do teshuvah and to rectify his thoughts; therefore he is distanced from the sin.

The mirror image of the schemer: there, sinning corrupted his teshuvah; here, the very fear of sin spurred genuine teshuvah and purified his thoughts, so the sin itself is pushed far away from him.

Summary: Just as one who plans "I will sin and repent" corrupts teshuvah itself and is therefore denied the chance to repent, the opposite holds with even greater force: one who, out of fear of sin, does teshuvah already over his stray thoughts before any actual transgression — "the man of iniquity his thoughts" — has his fear of sin spur a true rectification, and Heaven saves him from sin entirely.