Whatever we dwell on at the point of death has a powerful effect on what happens to us in after death. Krishna seems to be saying that part of your karma will be unpacked, which corresponds to what you're dwelling on. It's always good to dwell on something positive, high, especially spiritual at the point Of Death.
Swami Sarvapriyananda teaches Chapter 8 (Verses 23-28) of the Bhagavad Gita. In this series of talks, Swami Sarvapriyananda unfolds the highest truths of Vedanta through the study of the Bhagavad Gita (The Song of God).