God decided Jerusalem to be the center for the children of Israel, as He planned Makka to be the center for the children of Ishmael. For Baitul Maqdas Kaba was the Qibla, the way we follow the direction of the Kaba in our mosques. The religion was the same, that is, Islam. Later, they split as we have different sects in Islam. Judaism and Christianity are the sects of Islam.
God says in the Quran:
شَرَعَ لَكُم مِّنَ الدِّينِ مَا وَصَّىٰ بِهِ نُوحًا وَالَّذِي أَوْحَيْنَا إِلَيْكَ وَمَا وَصَّيْنَا بِهِ إِبْرَاهِيمَ وَمُوسَىٰ وَعِيسَىٰ ۖ أَنْ أَقِيمُوا الدِّينَ وَلَا تَتَفَرَّقُوا فِيهِ ۚ
[O Prophet!] We have sent to you and whose directive We gave to Abraham, Moses, Jesus: “Adhere to this religion [in your lives] and do not create difference in it (42: 13)