Gita 04.07 explained
yadā yadā hi dharmasya
glānir bhavati bhārata
tadātmānaṁ sṛjāmy aham
Word for word:
yadā yadā — whenever and wherever; hi — certainly; dharmasya — of religion; glāniḥ — discrepancies; bhavati — become manifested; bhārata — O descendant of Bharata; abhyutthānam — predominance; adharmasya — of irreligion; tadā — at that time; ātmānam — self; sṛjāmi — manifest; aham — I.
Whenever and wherever there is a decline in religious practice, O descendant of Bharata, and a predominant rise of irreligion – at that time I descend Myself.
Yada-Yada -> Wherever and whenever
4.4 -> Arjuna asked question about Sun god coming earlier then Krishna
4.5 -> Krishna said I remember my previous life but you don’t
4.6 -> and then He talks about His own position. Krishna says He remembers because His body is transcendental. I am lord of all living beings and I come by my own nature, my own transcendental form by my mercy.
Now in 4.7 Lord will describe why He appears in this material world
There is always fight between dharma and adharma within us, the higher self and the lower self, both are prompting us to act in their ways, same conflict is reflected in external world as conflict between good and evil. What is actually good and bad to understand or know that people has to refer the scripture.
Dharma is having multiple meaning. Normally dharma referrers to our essential nature as explained by Srila Prabhupad, but it has other meanings also. For example Krishna says Serva Dharma parityaja so if it is our essential nature how can we give it up, so it indicated other meaning.
Essentially it refers to three different things ultimately it refers to essential nature which is to Love Krishna which is spiritual nature, but we are not at spiritual nature of consciousness we are at material nature of consciousness we have material dharma which is given by Varnasharam, which keeps us in harmony with world around us and fulfil our necessity, condition dharma or svadharma or material dharma, but varnasharma is a gradual progress of purification.
Sadhana Bhakti is transitional dharma, it is not eternal dharma, Bhakti is eternal dharma.
Here Krishna is talking to social arrangement by which people practice principle of spirituality.
Srila Prabhupad Purport: The word sṛjāmi is signiﬁcant herein. Sṛjāmi cannot be used in the sense of creation, because, according to the previous verse (Although I am unborn and My transcendental body never deteriorates, and although I am the Lord of all living entities, I still appear in every millennium in My original transcendental form.), there is no creation of the Lord’s form or body, since all of the forms are eternally existent. Therefore, sṛjāmi means that the Lord manifests Himself as He is.
Based on our bagging in mind we pursue words in different ways… for example when kama is used in spiritual world it is different it is pure spiritual selfless attraction, but we take it in other way. Rasa Panch adhaya says that it removes lust so how can it increases lust.
So on one level dharma is transcendental nature but Srila Prabhupad also said Dharmas Tu Saksad Bhagvat Pranitam, it is given by God. Essential principle is Lord wants souls to return back home, so for this several things are present e.g. scripture, His own manifestation (Sometimes He descends personally, and sometimes He sends His bona ﬁde representative in the form of His son, or servant, or Himself in some disguised form.) Sometimes externally it will look different, as when Lord appear as Buddha he denied Vedas because of situation present that time but He has given same principle and since He is God, by following Him also people become elevated, at least from lower modes to mode of goodness.
So sometime people says this is the only way or this is last incarnation of God or last massager of Lord, Lord is so great that we cannot restrict or limit Him. It depicts idea of Lord being very narrow. For returning to God there are certain ways but everyone can advance by following different or their own religion.
Krishna is not saying that I am the only incarnation, whenever and wherever there is need based on this verse He will appear so it is very broad and inclusive vision.
There are differences in various religions so how we will understand this? There are higher and lower principle. There is exoteric and esoteric. Exoterics may be different as Hindus fold their hand and Muslims making hand gesture are different, Christens may do remoras but principle is same as offer respect to God. So internal is same but external is different.
Srila Prabhupad purport: The whole purpose of the mission of incarnations is to arouse Kṛṣṇa consciousness everywhere. Such consciousness is manifest and nonmanifest only under different circumstances.
So it is already present within us this has to be aroused, here Krishna consciousness is also taken as God consciousness.