2.14 'In the case of a man who knows that the Self is eternal, although there is no possibility of delusion concerning the destruction of the Self, still delusion, as of ordinary people, caused by the experience of cold, heat, happiness and sorrow is noticed in him. Delusion arises from being deprived of happiness, and sorrow arises from contact with pain etc.' apprehending this kind of a talk from Arjuna, the Lord said, 'But the contacts of the organs,' etc.
Matra-sparsah, the contacts of the organs with objects; are sita-usna-sukha-duhkha-dah, producers of cold, heat, happiness and sorrow. Matrah means those by which are marked off (measured up) sounds etc., i.e. the organs of hearing etc. The sparsah, contacts, of the organs with sound etc. are matra-sparsah. Or, sparsah means those which are contacted, i.e. objects, viz sound etc. Matra-sparsah, the organs and objects, are the producers of cold, heat, happiness and sorrow.
Cold sometimes produces pleasure, and sometimes pain. Similarly the nature of heat, too, is unpredictable. On the other hand, happiness and sorrow have definite natures since they do not change. Hence they are mentioned separately from cold and heat. Since they, the organs, the contacts, etc., agamapayinah, have a beginning and an end, are by nature subject to origination and destruction; therefore, they are anityah, transient. Hence, titiksasva, bear; tan, them  cold, heart, etc., i.e. do not be happy or sorry with regard to them.