After receiving green-card, how long do I need to stay with current employer?

[marica.marius]

If I leave my employer after 4 months of receiving green-card, can my employer withdraw the I-140 or the green-card?

Will that affect my naturalization application?

[Enub4]

From other site:

The law does not set a specific amount of time that an individual must remain with a sponsoring employer after the green card is issued. However, if the individual moves to a new job shortly after receipt of an EB green card, this could be viewed by the U.S. Citizenship and Immigration Services (USCIS) as evidence that the green card holder never intended to remain in the position. The USCIS could use this as a basis to call into question the validity of the green card.

If the USCIS believes that the beneficiary did not intend to remain in the sponsored position, the USCIS could try to rescind (i.e., revoke) the green card altogether. However, the USCIS typically can rescind a green card only within five years of its issuance. In many cases, the USCIS does not learn that a foreign national quickly moved to a new employer until the individual files an application for naturalization (form N-400), which often does not occur until more than five years have elapsed since the green card was issued. This is one reason that rescission based on a job change is rare.

and

With no set timeframe in place, it can be difficult to gauge when a move to a new job may be a cause for concern. Many immigration practitioners tend to suggest that remaining in the sponsored position for six-to-twelve months following the issuance of the green card likely is sufficient to evidence that the sponsored employee / beneficiary acted in good faith.

This is a general guideline, though, not a set rule. The inquiry from the USCIS is case-specific. No doubt, there are situations in which factors may arise after the green card is issued that legitimately may lead an employee to move to a different employer in less than six-months’ time.

If a change in circumstance requires an individual to move to a new employer relatively soon after a green card is issued, it would be wise to keep evidence of that compelling reason for the job change. In addition, it is good practice to retain evidence of having worked in the sponsored position after the green card was approved (e.g., W-2s, paystubs), even if it was for a fairly short period of time.