श्रीमद्वाल्मीकिरामायणे अरण्यकाण्डे द्वादशस्सर्गः (२७ श्लोकम)
After completing Agnihotra (naivedya, Vaisvadevam), Agastya performed Atithipooja of Seeta-Raama-Lakshmanas by offering Arghya-paadyams and then offering food as per his ashrama-dharma, which is Vaanaprastham.
Through this shloka Valmiki Maharshi is teaching us the sequence of things that need to be done in Atithi Pooja. First the host must finish his Devata-Pitrudevata aaraadhana (Agnihotra, Naivedya, Vaisvadevams). Then he must offer arghyam and paadyam to the atithis. Then as per his own varna-ashrama dharmas, he must make arrangements for food to the atithis.