This verse is found in the Padyāvalī (82).
The form of Syamasundara is the supreme form, the city of Mathura is the supreme abode, Lord Krsna's fresh youth should always be meditated upon, and the mellow of conjugal love is the supreme mellow
Expressions researched:
"The form of Śyāmasundara is the supreme form, the city of Mathurā is the supreme abode, Lord Kṛṣṇa’s fresh youth should always be meditated upon, and the mellow of conjugal love is the supreme mellow"
Sri Caitanya-caritamrta
CC Madhya-lila
“‘The form of Śyāmasundara is the supreme form, the city of Mathurā is the supreme abode, Lord Kṛṣṇa’s fresh youth should always be meditated upon, and the mellow of conjugal love is the supreme mellow.’”.
“‘The form of Śyāmasundara is the supreme form, the city of Mathurā is the supreme abode, Lord Kṛṣṇa’s fresh youth should always be meditated upon, and the mellow of conjugal love is the supreme mellow.’”