Some teachings associated with death found in the Bhagavad Gita.
Indeed, certain is death for the born, and certain is birth for the dead; therefore, over the inevitable, you should not grieve. (2.27)
He who is able, while still here (in this world) to withstand, before the liberation from the body (death), the impulse born out of desire and anger, he is a Yogin, he is a happy man. (5.23)
And whosoever, leaving the body, goes forth remembering Me alone, at the time of his death, he attains My being; there is no doubt about this. (8.5)
At the time of death, with an unshaken mind full of devotion, by the power of ‘yoga’ fixing the whole ‘prana’ (breath) between the two eyebrows, he (the seeker) reaches the Supreme Resplendent ‘PURUSHA.’ (8.10)
If the embodied one meets with death when Sattwa Guna is predominant, then he attains to the spotless worlds of the "Knowers of the Highest’. (14.14)
Meeting death in Rajas Guna, he is born among those attached to action; and dying in Tamas Guna, he is born in the womb of the senseless. (14.15)
Whatever is sacrificed, given or performed, and whatever austerity is practised without faith, it is called 'A-SAT, ' O Partha; it is not for here or hereafter (after death). (17.28)