In plain words
After Rāma had come back to Ayodhyā, a washerman: “Śrī Rāma has taken back Sītā, who stayed ten months in Laṅkā. I am not such a fool,” he said. When this talk reached Rāma, he gave up Sītā, whom he had chosen in marriage with the sacred fire as witness. Even so, Sītā's mind did not waver for one moment. She went on thinking of Rāma alone, without a break. For that very reason Sītā is a wife of great fidelity. No other person equal to such a Sītā is seen in the world. Rāma incarnated to proclaim to the world such a steady principle of Bhakti.
When He played with the Gopīs, Kṛṣṇa was only seven!
After that, in the Dvāpara age, Śrī Kṛṣṇa incarnated and showed many līlās. But no one recognised the principle of Kṛṣṇa's character. The Gopīs were much older in years. At the time of His līlās with them, Kṛṣṇa was seven years old. How laughable to say that a boy of seven played līlās with the Gopīs! As one plays at a mother's side, Kṛṣṇa played at the side of the Gopīs. But unable to grasp this truth, people made up many kinds of false notions, ‘Kṛṣṇa is a lover of the Gopīs’, and brought dishonour on Kṛṣṇa. Like Śrī Rāma, Śrī Kṛṣṇa too showed forth His divinity and His ideal humanity and stood as an ideal for the world.
In every age God takes on many kinds of Avatāras to protect the devotees. He comes not only to protect the devotees but also to set right the minds of the devotees. In the Dvāpara age Kṛṣṇa was born to Devakī and Vasudeva and grew up with Yaśodā and Nanda. He was born to Devakī and Vasudeva. But the name came to Yaśodā and Nanda alone. Kṛṣṇa showed many wonders. He slew the wicked Kaṃsa. He took away the crookedness of the misshapen Kubjā. He ended Kucela's distress. Kucela was Kṛṣṇa's boyhood friend; he lived on in crushing poverty. He had many children. He had not the means even to fill their stomachs with food.