During the period of Lord Krsna's appearance, the killing of asuras or nonbelievers such as Kamsa and Jarasandha was done by Visnu, who was within the person of Sri Krsna. Such apparent killing by Lord Sri Krsna took place as a matter of course and was an incidental activity for Him. But the real purpose of Lord Krsna's appearance was to stage a dramatic performance of His transcendental pastimes at Vrajabhumi, thus exhibiting the highest limit of transcendental mellow in the exchanges of reciprocal love between the living entity and the Supreme Lord. These reciprocal exchanges of mellows are called raga-bhakti, or devotional service to the Lord in transcendental rapture. Lord Sri Krsna wants to make known to all the conditioned souls that He is more attracted by raga-bhakti than vidhi-bhakti, or devotional service under scheduled regulations. It is said in the Vedas (Taittiriya Upanisad 2.7), raso vai sah: the Absolute Truth is the reservoir for all kinds of reciprocal exchanges of loving sentiments. He is also causelessly merciful, and He wants to bestow upon us this privilege of raga-bhakti. Thus He appeared as His own internal energy. He was not forced to appear by any extraneous force.