Skandapurana 14.22.35

14.22.35

na bhavadbhyasvahaṃ svargaṃ prayacchāmi kathaṃcana ..
dūto'vadhyo bhavedrājñāmapi vaire sudāruṇe ..
etasmātkāraṇāddūta na tvāṃ prāṇairviyojaye .. 35 ..

I will by no means give up heaven to you. / A messenger must not be killed by kings, even in the fiercest enmity; / for this reason, O messenger, I do not deprive you of your life. 35