《宋史·列传·卷二百三十一》
又召他到后苑延春殿奏对，郭药师拜伏在殿下，哭着说： 我在辽国，听说赵皇如在天上，不想今日能看到您的龙颜。 皇上非常赞赏他，委他以守燕重任，他回答说 ：愿效死力。 皇上又命令他捕取天祚帝而使燕人绝望，他脸色一变说： 天祚帝，是我的旧主，国破后逃走，我才投降。
又召对于后苑延春殿，药师拜廷下，泣言： 臣在虏，闻赵皇如在天上，不谓今日得望龙颜。 帝深褒称之，委以守燕，对曰： 愿效死。 又令取天祚以绝燕人之望，变色而言曰： 天祚，臣故主也，国破出走，臣是以降。
He was summoned again to the Yanchun Hall in the back palace for an audience. Guo Yaoshi prostrated himself and wept, saying, "When I was in Liao, I heard that the Zhao Emperor was as high as the heavens. I never imagined that I would see your imperial face today." The Emperor was very pleased with him and entrusted him with the heavy responsibility of defending Yan. He answered, "I am willing to serve loyally until death." The Emperor then ordered him to capture Emperor Tianzuo and crush the spirits of the Yan people. His face changed, and he said, "Emperor Tianzuo was my former master. Only after the country was destroyed and he fled did I surrender.