Bhagavad-Gita: Chapter 2, Verse 10

Rudra Vaisnava Sampradaya:

Visnuswami

Sridhara Swami's Commentary

What happened then after this? In answer it is stated: to Arjuna who was lamenting between the two armies the Supreme Lord spoke as if smiling , meaning spoke with a beaming countenance.

Brahma Vaisnava Sampradaya:

Madhvacarya

Madhvacarya's Commentary

Lord Krishna, the resplendent one, situated between the 2 armies, with a slight smile upon His face spoke to the grief stricken Arjuna who was enveloped by the entanglement of fraternal delusion.

Sri Vaisnava Sampradaya:

Ramanuja

Ramanuja's Commentary

Observing Arjuna overwhelmed with grief at not properly perceiving the actual distinction between the physical body and the soul and yet discoursing in the way that one with proper knowledge of the soul existing independent of the body would expound; seeing him in the predicament of having conflicting views, beholding him languishing with inactivity when both the opposing armies were ready for battle; Lord Krishna smilingly began to instruct him in the very next verse beginning na tv evaham jatu nasam meaning never was there a time I did not exist, all the way through to Chapter 18, verse 66 ending aham tvam sarva-papebhyo moksayisyama ma sucah meaning I shall deliver you from all sinful reactions do not fear. Encapsulated within the threefold doctrines of Karma Yoga, Bhakti Yoga and Jnana Yoga which are the sole means for realising and then acquiring knowledge of the true nature of the individual consciousness and the science of attaining communion with the Ultimate Consciousness.

It should be noted although Arjuna was lamenting the word prahasan means smiling. This indicates that Lord Krishna discoursed on these most esoteric subject matters regarding the nature of the soul and the difference between the material and spiritual manifestations while in the mood of enjoying a pleasurable recreation.

Kumara Vaisnava Sampradaya:

Nimbaditya

Kesava Kasmiri's Commentary

In this way although Arjuna had decided to refrain from the battle still Dhritarastra should not expect that the future of his sons was to be bright and happy as long as the Supreme Lord Krishna, the controller of the animate and inanimate who descended personally to destroy the miscreants is present in this world. To emphasize this reality Sanjaya said to him O Bharata referring to his anscestor, the great monarch of all the world King Bharata telling frankly that the joy he is feeling regarding Arjuna's seemingly abstention from the battle and the termination of the war was not appropriate. Lord Krishna with a subtle smile upon his face then spoke to Arjuna who was lamenting at a most inappropriate time between the 2 opposing armies. The word prahasan meaning smiling is used to subtlely indicate sarcasam and evoke anger at the impropriety of such limpid sensitivity by Arjuna who in his own right is a mighty warrior respected and reknowed by all the mightiest warriors of his time. This smile indicating sarcasm is justified by the use of the word iva as it were indicating that due to the nature of the situation, being the 2 armies immeadiately ready for battle, Arjunas reluctancy and Lord Krishna accepting him as a disciple. So in order to substantiate Arjunas fitness to receive spiritual knowledge this subtle smile is used to remove any lingering vestiges of pride Arjuna might have had regarding his knowledge, intelligence and prowess.