There is a popular belief that the Vedas have section like jnana kanda and karma kanda.
Is there any such statement in the Vedas which talks of such kAndams?
The subject matter of the whole Veda is divided into Karma- Kanda, Upasana-Kanda and Jnana-Kanda.
The Karma-Kanda or "Ritualistic Section deals with various sacrifices and rituals".
The Upasana-Kanda or "Worship-Section deals with various kinds of worship or meditation".
The Jnana-Kanda or "Knowledge-Section deals with the highest knowledge of Nirguna Brahman".
The Mantras and the Brahmanas constitute -> Karma-Kanda; the Aranyakas Upasana - Kanda; and the Upanishads Jnana-Kanda.
According to Sri Sankara, [Phala (end result or the objective)]: "Karma-kanda aspires for worldly prosperity and heavenly pleasures. The aim of Jnana-kanda, he said, is liberation (Moksha). Further, he pointed out that Brahma Sutra says (3.5.36-37) even those who do not perform rituals are qualified to gain knowledge".
Karma Kanda is the section of the Vedas that lists rituals, ceremonies and actions, which, when performed, lead one to enjoyment and power. On the other hand, Jnana Kanda, comprising the philosophical teachings of the Upanishads, deals with the liberating knowledge and disclaims action as a means of attaining liberation. It would appear that these sections are fundamentally contradictory.
the three categories karma, jnana and upasana kanda appears to be divisions made later on by those analysing the vedas. about the contradictions between the various ways to attain the Ultimate truth, it is not surprising as Supreme Brahman/ Ultimate Truth is infinite and hence all contradictory methods finally leads to this, when sincerely followed. There cannot be one single path to attain infinite Truth.
Hindu philosophy refers to a group of Shad-darshanas.
Of these six the 'Meemamsa' and 'Vedanta' philosophies contradict each other.
The aim of Mimamsa is to provide a philosophical justification for the observance of ritual. Because Mimamsa is concerned with the earlier parts of the Vedas it is also referred to as Purva-Mimamsa (“Prior Study”) or Karma-Mimamsa (“Study of Actions”) or Karmakanda.
Codana-laksano 'rtho dharmah: "Duty is that which is indicated by the injunctions of the Vedas."(Mimamsa Sutra 1.1.2)
Vedanta, which deals with the later portion of Vedic literature called the Upanishads, is called Uttara-Mimamsa (“Posterior Study”) or Jnana-Mimamsa (“Study of Knowledge”) or Jnana-kanda.
Through continuous pursuit of Satya (truthfulness), Tapas (perseverance, austerity), Samyajñāna (correct knowledge), and Brahmacharya, one attains Atman (Self, Soul). — Mundaka Upanishad, 3.1.5
So what you need to recognise is that; you cannot find distinct sections or texts with headings or titles like Karma-kanda and Jnana-kanda among the Vedas. Basically they are two philosophies that are distinct from one another and contradict each other, which are discussed through out Vedas. Since the two philosophies stand distinct from one another, they are referred to by names that distinguish them.
One, the Karma-kanda philosophy advocates the attainment of worldly riches by pleasing the gods through conducting the rituals strictly as suggested in the Vedas and the other the Jnana-kanda philosophy, advocates attaining enlightenment by seeking true knowledge.
Hope that helps resolving your query.