इत्यादिश्रुतिस्मृतीतिहासपुराणवचनेभ्यः ।मङ्गलानां च मङ्गलं मङ्गलं सुखं तत्साधनं तज्ज्ञापकंच, तेषामपि परमानन्दलक्षणं परं मङ्गलमिति मङ्गलानांच मङ्गलम् ।दैवतं देवतानां च देवानां देवः, द्योतनादिभिःसमुत्कर्षेण वर्तमानत्वात् ।भूतानां यः अव्यय: व्यय-रहित: पिता जनकः यो देवः, सः एकं दैवतं लोके इतिवाक्यार्थः ॥
In plain words
Drawing from the declarations of scripture, tradition, epic, and legend: He is the very blessing within all blessings, grace itself, happiness, the path to it, and the revealer of that joy. Above all, He is supreme auspiciousness defined by supreme bliss—hence the designation 'auspicious of the auspicious'. He is the deity among deities and the god among gods, shining with peerless preeminence. He who is the imperishable, decayless father and generator of all beings—that God alone is the singular divinity in this existence; this is the true import of the teaching.
Close to the Sanskrit
From the statements of the Sruti, Smriti, Itihasa, and Purana: He is the auspiciousness of auspicious things, auspicious, happiness, the means thereof, and the revealer of that; and among those too, supreme auspiciousness characterized by supreme bliss, thus 'the auspiciousness of auspicious things'. He is the deity of deities and the god of gods, because He exists with preeminence through illumination and other qualities. He who is the imperishable, decay-free father and progenitor of beings—that God is the one deity in the world, this is the meaning of the sentence.