In plain words
Whenever Changes Contrary to the Vedas and Śāstras Occur, God Comes Down in Some Form
Whenever there is a decline of Dharma, O Bhārata, and a rise of Adharma, then I bring Myself forth.
Whenever Dharma declines, whenever injustices flourish, whenever changes contrary to the Veda take place, whenever conduct against the Śāstras begins, at such a time God, or the power of God, or avadhūtas come down to set right what has gone contrary. That is what the Arcana-nāmas are. Within these Arcana-nāmas, some great souls arise in the world in the form of aṃśas, with the aim of revealing the principle of God in full; that is, they are called aṃśāvatāras. Vibhava Avatāras, Pūrṇa Avatāras. Arcana-nāmas, aṃśāvatāras. From time to time Avatāras of this kind have arisen, in every country too! Not in Bhārata alone. Jesus too first said, ‘I am the messenger of God.’ ‘I am God's messenger,’ He said. What kind of messenger? There are two kinds of messengers. One is the avadhūta, the other the yamadūta. The yamadūtas are messengers who torment; the avadhūtas are messengers who protect. So, at the very first, He said ‘I am the messenger of God’. Step by step He came to recognise this principle of the Antarātma. Then He said, ‘I am the son of God.’ What does that mean? When He is the son of God, He has a right in God's property. The son has a claim on the father's property. All such sacred good thoughts, good reflections and good qualities went on arising in Him. Only then did He say, ‘I am the son of God.’ Once that property has passed to the son, the father has no other property left. He handed everything over to the son. He recognised this truth. What is in that and what is in this are one and the same. The Ātma is one! Sarvātma-bhāva. Then He said, ‘I and My Father are one.’ In the same way, in Persia too, they came first as messengers. Muhammad. He came as a messenger. He said, ‘I am in the light.’ He said, ‘God dwells in heaven; I live in His light.’ Step by step He came to recognise this divinity.