The Holy Quran confirmed that with them because the sender is One; Allah (swt):

شرَعَ لَكُم مِّنَ الدِّينِ مَا وَصَّىٰ بِهِ نُوحًا وَالَّذِي أَوْحَيْنَا إِلَيْكَ وَمَا وَصَّيْنَا بِهِ إِبْرَاهِيمَ وَمُوسَىٰ وَعِيسَىٰ ۖ أَنْ أَقِيمُوا الدِّينَ وَلَا تَتَفَرَّقُوا فِيهِ

(He has ordained for you of religion what He enjoined upon Noah and that which We have revealed to you, [O Muhammad], and what We enjoined upon Abraham and Moses and Jesus – to establish the religion and not be divided therein.) (Ash-Shura: 13)

(… آمِنُوا بِمَا نَزَّلْنَا مُصَدِّقًا لِّمَا مَعَكُم مِّن قَبْلِ أَن نَّطْمِسَ وُجُوهًا فَنَرُدَّهَا عَلَىٰ أَدْبَارِهَا …) (…believe in what We have sent down [to Muhammad], confirming that which is with you, before We obliterate faces and turn them toward their backs …): Addressing who were given the Scripture, ordering them to believe in the Quran, otherwise, their faces will be effaced and turned backwards. This is a threatening.

(… أَوْ نَلْعَنَهُمْ كَمَا لَعَنَّا أَصْحَابَ السَّبْتِ …) (…or curse them as We cursed the sabbath-breakers …): Who are the people of the Sabbath? They are a group from the Jews, – Later verses will come related to the people of the Sabbath – Allah (swt) prevented them from working on this day (the Sabbath). Because of their many denial, Allah (swt) tested them by making the fish swim close to the surface of the water , on the day which they were prohibited to fish (Saturday), whereas the fish would be hidden from them on the day when they were allowed to fish. They wanted to circumvent the order of Allah (swt), so they put wires to seize the fish that come on Saturday, and on the next day they collected them. This is a fraud against Allah’s law, and it would have been better for them if they had adhered to His commands and were patient and had not fished on Saturday.