Those are a people that have passed away; for them is what they earned, and for you shall be what you earn; and you shall not be questioned as to what they did. (2:135) more translations
The preceding verses mention a number of prophets. This verse declares the prophets of the bygone days all dead. For them is what they earned, meaning their accounts are closed and their actions have come to an end. There is a finality and closure as far as their actions are concerned, so also there is a separation between us and them. This verse is in fact a corollary of Holy Prophet Muhammadsaw being the Khataman Nabiyeen, the Seal of the Prophets. Earlier prophets have no unfinished business left and hence there is no need to keep any of them unnaturally alive in the recesses of the heavens. In other words, it is not their problem anymore. The task of spreading the message of God is in the safe and capable hands of the Holy Prophet of Islam, may peace and blessing of Allah be upon him. All spiritual blessings and ranks now flow through his person. Holy Prophetsaw is in no need of help from a prophet sent to another people. Through his power of spiritual purification he is capable of raising such souls from among his own people as would help him in his mission, some of whom may even reach the status of a prophet while staying subservient to him. That is entirely consistent with his status of Khataman Nabiyeen, whereas the return of an earlier prophet to rescue his mission, a prophet who received nothing by way of spiritual food from him, is a rank insult and is tantamount to breaking that seal.