Bhagavad Gita 9.23

येऽप्यन्यदेवता भक्ता यजन्ते श्रद्धानविता: |
तेऽपि मामेव कौन्तेय यजन्त्यविधि निकम्

Translation

O son of Kunti, even those devotees who faithfully worship other gods also worship Me. But they do so by the wrong method.