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MM mantra 7

cintayāmi harim eva santataṁ
manda-hāsa-muditānanāmbujam
nanda-gopa-tanayaṁ parāt paraṁ
nāradādi-muni-vṛnda-vanditam
Synonyms: 
cintayāmi — I think; harim — about Lord Hari; eva — indeed; santatam — always; manda — gentle; hāsa — with a smile; mudita — joyful; ānana-ambujam — whose lotus face; nanda-gopa — of the cowherd Nanda; tanayam — the son; parāt param — the Supreme Absolute Truth; nārada-ādi — beginning with Nārada; muni-vṛnda — by all the sages; vanditam — worshiped.
Translation: 
I always think of Lord Hari, whose joyful lotus face bears a gentle smile. Although He is the son of the cowherd Nanda, He is also the Supreme Absolute Truth worshiped by great sages like Nārada.
Purport: 

As King Kulaśekhara thinks of the Lord and remembers His happiness, the king also becomes happy. Lord Kṛṣṇa is eternally happy, but the conditioned soul is mostly unhappy. When we live in forgetfulness of our spiritual nature, even our so-called bliss is illusion—it is unsatisfying, flickering pleasure (capala-sukha). The poet Govinda dāsa expresses this in his song Bhajhuṁ re mana: "What assurance is there in all one's wealth, youthfulness, sons, and family members? This life is tilting like a drop of water on a lotus petal. Therefore you should always serve the divine feet of Lord Hari."

Another Vaiṣṇava poet, Narottama dāsa Ṭhākura, has expressed the happiness of the Supreme in a song addressed to Lord Caitanya and Lord Nityānanda: hā hā prabhu nityānanda premānanda-sukhī kṛpāvalokaṇa koro āmi baḍo duḥkhī: "My dear Lord Nityānanda, You are always joyful in spiritual bliss. Since You always appear very happy, I have come to You because I am most unhappy. If You kindly cast Your glance upon me, I may also become happy."

In this prayer King Kulaśekhara reveals himself to be at the stage of spontaneous love of God, in which the devotee goes beyond mere formal ceremonies and ritual recitations and thinks of Lord Hari always. This is the actual standard of happiness in devotional service. Such constant remembrance of the Lord is possible through constant chanting of His name. As Lord Caitanya recommends in His Śikṣāṣṭaka (3), kīrtanīyaḥ sadā hariḥ: [Cc. Ādi 17.31] "One should always chant the holy name of the Lord." In this way one will always be happy in the joy of Lord Kṛṣṇa. The Lord's happiness is always increasing, like an ever-expanding ocean (ānandāmbudhi-vardhanam), and the living entity is meant to dive into that ocean because his original nature is to be ever-blissful in contact with the Lord.

King Kulaśekhara further hints at the unlimited happiness of Kṛṣṇa consciousness when he describes Lord Kṛṣṇa as the son of Nanda Gopa. Kṛṣṇa is the Lord of Vaikuṇṭha, and He expands Himself as the catur-vyūha, as the puruṣa-avatāras, and as many other forms. But His original form is a cowherd boy in Goloka Vṛndāvana. He came to Vṛndāvana-dhāma within this world to reciprocate loving exchanges with His pure devotees here who wished to be His friends, parents, and lovers. They cherished the desire to serve the Lord in intimate ways, and they finally fulfilled it after, as Śrīla Prabhupāda says in his Kṛṣṇa book, "accumulating heaps of pious activities." In other words, after they had perfected their loving devotion to the Lord through many lives of service, He appeared in person to reciprocate with them in their specific mood.

Kṛṣṇa enjoyed playing as the son of Nanda. For example, Kṛṣṇa would sometimes delight His parents by carrying His father's wooden slippers on His head, just like an ordinary child. And Kṛṣṇa would also enjoy His magnificent pastimes in Dvārakā, where He lived in unequaled opulence in 16,108 palaces with an equal number of queens. Nārada once visited the Lord at Dvārakā and saw Him engaging in various pastimes in His many palaces. At that time Nārada became astounded and described Him as the source of all opulences.

There is no contradiction between Kṛṣṇa's charmingly sweet pastimes in the simple village of Vṛndāvana and His magnificently opulent pastimes in Dvārakā. All of the Lords pastimes are oceans of happiness. And the devotee who can always think of the Lord performing any of His multifarious pastimes dives into that ocean. Even in this world, one who always thinks of the Lord will forget all material miseries and enter the spiritual abode.