He (Lord Krsna) takes pleasure when His pure devotee beats Him like an enemy or rebukes Him from a superior position, although no one can be superior to the Lord
SB Canto 1
May He, Lord Śrī Kṛṣṇa, the Personality of Godhead, who awards salvation, be my ultimate destination. On the battlefield He charged me, as if angry because of the wounds dealt by my sharp arrows. His shield was scattered, and His body was smeared with blood due to the wounds.
The dealings of Lord Kṛṣṇa and Bhīṣmadeva on the Battlefield of Kurukṣetra are interesting because the activities of Lord Śrī Kṛṣṇa appeared to be partial to Arjuna and at enmity with Bhīṣmadeva; but factually all this was especially meant to show special favor to Bhīṣmadeva, a great devotee of the Lord. The astounding feature of such dealings is that a devotee can please the Lord by playing the part of an enemy. The Lord, being absolute, can accept service from His pure devotee even in the garb of an enemy. The Supreme Lord cannot have any enemy, nor can a so-called enemy harm Him because He is ajita, or unconquerable. But still He takes pleasure when His pure devotee beats Him like an enemy or rebukes Him from a superior position, although no one can be superior to the Lord. These are some of the transcendental reciprocatory dealings of the devotee with the Lord. And those who have no information of pure devotional service cannot penetrate into the mystery of such dealings. Bhīṣmadeva played the part of a valiant warrior, and he purposely pierced the body of the Lord so that to the common eyes it appeared that the Lord was wounded, but factually all this was to bewilder the nondevotees. The all-spiritual body cannot be wounded, and a devotee cannot become the enemy of the Lord. Had it been so, Bhīṣmadeva would not have desired to have the very same Lord as the ultimate destination of his life. Had Bhīṣmadeva been an enemy of the Lord, Lord Kṛṣṇa could have annihilated him without even moving. There was no need to come before Bhīṣmadeva with blood and wounds. But He did so because the warrior devotee wanted to see the transcendental beauty of the Lord decorated with wounds created by a pure devotee. This is the way of exchanging transcendental rasa, or relations between the Lord and the servitor. By such dealings both the Lord and the devotee become glorified in their respective positions. The Lord was so angry that Arjuna checked Him when He was moving towards Bhīṣmadeva, but in spite of Arjuna's checking, He proceeded towards Bhīṣmadeva as a lover goes to a lover, without caring for hindrances. Apparently His determination was to kill Bhīṣmadeva, but factually it was to please him as a great devotee of the Lord. The Lord is undoubtedly the deliverer of all conditioned souls. The impersonalists desire salvation from Him, and He always awards them according to their aspiration, but here Bhīṣmadeva aspires to see the Lord in His personal feature. All pure devotees aspire for this.