In plain words
The devotees who come at the poet's call [those who seek only to serve]: From my father, his father, his father and his father, and their grandfather before them, seven generations back, we have come at the due times and done service in due order, without a break. On the holy festival of Tiruvōṇam we sing "many years, many thousands of years" to the one who, at the lovely hour of dusk, took the form of the man-lion [Narasiṃha] and destroyed the foe [Hiraṇyakaśipu, enemy of his devotee Prahlāda], so that his weariness from that day may pass.