Manavala Mamunigal is considered the avatara of Swami Ramanuja. There are many ways to demonstrate this. Some are shown below.
1. Both Emberumanar and Mamunigal have affinity to writing vyakhyanams more than anything else. Ramanuja has graced us with vyakhyanams such as Sri Bhashyam, Vedanta Deepasaram and Gita Bhashyam. Mamunigal’s vyakhyanams for rahasya granthas are well known. Just as Ramanuja wrote a few original works such as Vedartha Sangraham and Gadya Trayam, Mamunigal too has written some such as Yatiraja Vimshati and Upadesa Ratthinamalai.
2. There are many who fill their works with reproach and mockery of others and their works. Neither Ramanuja nor Mamunigal allow even an iota of that to enter their works, leaving them as the most pure Srisooktis.
3. Both Ramanuja and Mamunigal fill their works all over with the innermost meanings of Sastras, thereby pleasing the hearts of scholars.
4. At the beginning of Sri Bhashyam, Ramanuja clearly shows his devotion to the pUrvAcharyas works (“bhagavad bhOdAyana krutAm …”). Mamunigal also shows the same in Upadesa Ratthinamalai (“munnOr mozhintha muRai thappAmal …”) and else where (“munnavarAm nam kuravar mozhigaL uLLap peRROm”). In addition, he has filled his vyakhyana granthas with the words of pUrvAcharyas.
5. Both Ramanuja and Mamunigal are celebrated for growing and spreading the words of Nammazhvar. Ramanuja’s vAzhi thirunAmam says “mARanurai seydha thamizh maRai vaLarththOn vAzhiyE”. One of the Thiruvaymozhi thaniyan goes
sIrAr sadagOpan senthamizh vEdham tharikkum
pErAdha uLLam peRa
Eyndha perum kIrththi irAmAnusa muni than
vAyndha malarppAdham vaNangukinREn”.
In this matter, is it necessary to even explain Mamunigal’s involvement? It is sufficient to quote one pasuram
“sERRuk kamala vayal sUzharangar tham sIr thazhaippap
pORRiththozhu nalla andhaNar vAzha ipbUthalaththE
mARRaRRa sempon maNavALa mAmuni vandhilanEl
ARRil karaiththa puLiyallavO thamizhAraNamE”
6. Ramanuja established 74 simhAsanAdipatis and through them conducted the darshana nirvAham. Mamunigal too established the ashta dikgajAchAryas (“thiramAga thikgajangaLittaruLum perumAL”) and through them conducted the darshana nirvAham.
7. Ramanuja had great affinity for all divyadesams (“manniya thennarangApuri mAmalai maRRum uvanthidu nAL”, “srirangam karaishailam anjanagirim …”). Mamunigal too demonstrated his great affinity for divyadesams by doing many yatras to them (“adaivudanE thiruppathigaL nadantha vErvai ARavO”).
Ramanuja showed affinity to Thirunarayanapuram that is not part of the 108 divyadesams and submitted the “oru nAyagamAy” Thiruvaymozhi pasuram to that kshetram and treated it like a divyadesam. Mamunigal too submitted the Thiruvaymozhi pasuram “thIrppArai yAmini” to Raja Mannar Kovil and treated it like a divyadesam.
8. That Ramanuja is the avatara of Adisesha is well known. This is explained in Garuda Vahana Pandita’s Divyasuri Saritam and in Vaduga Nambi’s Yatiraja Vaibhavam. That Mamunigal is also Adisesha’s avatara is shown in his life history and also in works such as Varavaramuni Shatakam.
9. Ramanuja greatly grew the wealth that is Srirangam. This is well established in Kozhil Ozhigu and in his vAzhi thirunAmam (“thennarangar selvam muRRUm thiruththi vaiththAn vAzhiyE”). This is the case for Mamunigal also. Does not this world say each day “aranga nagar vAzha innumoru nURRANdirum”.
10.Ramanuja was born north of Srirangam, in Sriperumbudur, to spread the Srivaishnava sampradhayam in both Sanskrit and in Tamil. Through his birth “nArANanaik kAttiya vEdham kaLipputradhu”, “thenkurugai vaLlal vAttamilA vaNthamizh maRai vAzhndhathu”. Manavala Mamunigal was born south of Srirangam, in Azhvar Thirunagari (“aranga nagarum mEvu thirunagariyum vAzhavandha maNavALa mAmuni”), in order to spread the sampradhayam in Tamil alone. Even though, Mamunigal is well versed in both languages, one is stressed to show his greater interest in it.
11.Even though Madhurakavi is the direct disciple of Azhvar, the final thiruvadi of Azhvar is Ramanuja (Azhvar’s padhukas are known as Ramanujan). Similarly, even though disciples such as Kooraththazhvan and Mudhaliandan are close to Ramanuja, Yatindra’s final thiruvadi is Yatindra Pravana.
12.Ramanuja brought out the meaning that Sriman Narayana is the Lord of all (“ellA uyirkatkum nAthan arangan”). Mamunigal brought out the meaning that Ramanuja is the saviour for all (“palluyirkkum viNNinthalai ninRu vIdaLippAn anaiththulagum vAzhappiRandha ethirAsa mAmunivan”).
13.Ramanuja’s vaibhavam was subdued until Mamunigal’s birth. Mamunigal is the lamp that brought the light to Ethiraja’s vaibhavam.
14.Their avataram is similar to that of Nara Narayana. Just as Narayana came as both acharya and sishya, so too Adisesha came as acharya and sishya.
15.Ramanuja brought out the greatness of Narayana (‘nArAyaNa vaibhava prakAsha’) while Mamunigal brought out the greatness of Ramanuja (‘rAmAnuja vaibhava prakAsha’).