In the Bhagavad-gītā you will find that vedaiś ca sarvair aham eva vedyaḥ (BG 15.15). Sarvaṁ vedam: "all Vedas." "All Vedas" means originally there was one Veda, Ṛg Veda, or somebody says Atharva Veda. Then, later on it was divided into four: Ṛg, Sāma, Yajur, Atharva. Then, from the Vedic injunction, then it was summarized, which is called Vedānta, summarized in sūtras: janmādy asya yataḥ (SB 1.1.1), athāto brahma jijñāsā.
In the sūtra there are so many meanings. Then the Upaniṣads, 108 Upaniṣads, they are also Vedic. Then they were explained further for ordinary men—the Purāṇas. They are also Vedas. Then it was further explained by Mahābhārata. So that is also Vedas. Rāmāyaṇa, that is also Vedas.
So any scripture, any literature, transcendental literature, whose aim is to understand God, that is Veda. Therefore anyone who is searching after the Supreme Lord, he is following the Vedic religion. This is another conclusion. The searching process may be different according to the country, climate, but if the ultimate goal is God, then that is accepted as religion. Just like Christian religion. Christian religion, they are also searching after God—Lord Jesus Christ advising, "Be lover of God." He presents himself as son of God. The Muhammadan, Muhammad, he also presented himself as servant of God. In this way, everyone is accepting.