Verse 1.9.4 (Hareesha Mji):
* Here, Bhishmadeva was getting ready to leave his body.
* The Pandavas and Lord Krishna came to him to pay their obeisances to Bhishmadeva. Even Lord Krishna bowed down to him.
* Here Srila Prabhupada comments that although Lord Krishna is the SPG, he still sometimes behaves like a human being. So one must not confuse him to be a human being. That will be clear when one reads BG completely and then the first 9 cantos of SB. That will help one develop faith on Lord Krishna as the SPG.
* As to why Krishna bowed down to Bhismadeva even though he knew Lord Krishna to be the SPG, for this Lord Krishna says in the BG: yad yad acharati.... Here the Lord is setting an example to us that how one should respect a pure devotee.
* Also, in order to show us how to surrender, the Lord came in the form of CM, a devotee and shows us how to surrender. And gave us this process of DS, how to execute bhakti.
* The Lord is so merciful that not only he gives us nice instructions, but also shows us by His example. It is up to us to take it sincerely.