This is a lyrical masterpiece of devotion of Vishnu by Sri Yamunacharya, the predecessor of Sri Ramanuja. Sanskrit text, with English transliteration, translation and notes.
Seek ye first the kingdom of God, and everything shall be added unto you. This is the one great duty, this is renunciation. Live for an ideal, and leave no place in the mind for anything else. Let us put forth all our energies to acquire that which never fails--our spiritual perfection. If we have true yearning for realization, we must struggle, and through struggle growth will come. We shall make mistakes, but they may be angels unawares.
-Swami Vivekananda