Why does Lord Kṛṣṇa describe the other three lower steps also, instead of describing onlythe topmost system of yoga?

Lord Krishna describes the other three lower steps of yoga in addition to the topmost system for several reasons:

1. Gradual Progression: The path to spiritual enlightenment is not an overnight journey. It requires gradual progression through different stages. By describing the lower steps, Lord Krishna provides a roadmap for this progression.

2. Different Levels of Readiness: Not everyone is at the same level of spiritual readiness. Some people may not be ready for the topmost system of yoga. The lower steps provide a starting point for these individuals.

3. Comprehensive Understanding: To fully understand the topmost system of yoga, one must also understand the lower steps. They provide the foundation upon which the topmost system is built.

4. Flexibility: Different paths may be more suitable for different people, depending on their individual circumstances, inclinations, and abilities. By describing all the steps, Lord Krishna allows for this flexibility.

5. Encouragement: By describing the lower steps, Lord Krishna also provides encouragement. It shows that everyone, regardless of their current level, can make progress on the path to spiritual enlightenment.