If Prophet Moosa (Peace be upon him) also comes, He will have to follow and imitate Prophet Muhammad (صلی اللہ علیہ وآلہ وسلم ))
If the Prophets who preceded Prophet Muhammad (صلی اللہ علیہ وآلہ وسلم ) arrived in the blessed time of Prophet Muhammad (صلی اللہ علیہ وآلہ وسلم ), they would have been His followers ( ummati) and not Prophets. And they would have followed Prophet Muhammad’s (صلی اللہ علیہ وآلہ وسلم ) Shariat. They would have had no other alternative other than following and copying Prophet Muhammad (صلی اللہ علیہ وآلہ وسلم ) as this tradition of Sunan Darmi, Kitab ul Muqaddimah says ”Syeduna Jabir (May Allah be well pleased with him) relates that once 'Umar bin Khattab (May Allah be well pleased with him) brought to the presence of the Holy Prophet (صلی اللہ علیہ وآلہ وسلم ) a copy of the Torah and said, O Prophet of Allah, this is a copy of the Torah. The Prophet (صلی اللہ علیہ وآلہ وسلم ) held His peace. Hadhrat Umar (May Allah be well pleased with him) started reading. The Prophet’s blessed face changed color. Hadhrat Abu Bakr Siddiq (May Allah be well pleased with him) said, May the wailing women wail on you, O Umar, Can’t You see the blessed face of the Prophet (صلی اللہ علیہ وآلہ وسلم )?
When Hadhrat Umar (May Allah be well pleased with him) saw the holy face of the Prophet (صلی اللہ علیہ وآلہ وسلم ), he said, I seek Allah’s protection from His anger and from the anger of His Prophet (صلی اللہ علیہ وآلہ وسلم ). We are satisfied with the Allah as our Lord, with Islam as our religion and with Hadhrat Muhammad (صلی اللہ علیہ وآلہ وسلم ) as our Prophet. Then the Prophet of Allah said, By him who holds the life of Muhammad (صلی اللہ علیہ وآلہ وسلم ) in His hand, if Moosa (peace be upon him) comes in this age and you start following him and leave me then you certainly stray from the right path. If he (Moosa) was here and present in my time then he would certainly follow me."
Hadhrat Shaykh Ul Islam, the founder of Jamia Nizamia, Imam Muhammad Anwarullah Farooqui writes in the explanation of this Hadith, “Now everybody can understand when such a small act of a sincere Companion like Hadhrat 'Umar‘s (May Allah be well pleased with him) agitated the Prophet (صلی اللہ علیہ وآلہ وسلم ) to such an extent then what about the speech of some Zaid and Umar which shakes the very belief of the Termination of Prophethood? How much do you think it would agitate the Prophet? Will it be forgiven? No, Never. Almighty Allah says in the Holy Quran, "Lo! those who malign Allah and His messenger, Allah hath cursed them in the world and the hereafter, and hath prepared for them the doom of the disdained." Surah Ahzab, Verse-57. All this from Anwaar e Ahmadi, pg no 55.