And this is greater than what they do in prostrating before a king or a nobleman of flocks and cattle, which are external actions. One who performs these actions towards one of the species of idolatry, even though his intention is not in worshipping it, is liable, as stated in Sanhedrin, Chapter 4: 'One who serves idolatry, one who seizes the altar, one who burns incense, one who pours libations, and one who prostrates himself,' and the Gemara asks: What does 'one who serves' mean?
Rabbi Yirmiyah said: It means one who serves according to its manner, and the same applies to 'one who seizes the altar,' 'one who burns incense,' 'one who pours libations,' and 'one who prostrates himself,' even if not according to its manner. And all the halachic decisors ruled that these four acts of service incur liability even if not according to its manner. And this practice is still observed among our brethren, the villagers and townspeople, that if one of them has an enemy seeking to harm him, he brings a lamb and slaughters it before his ruler to save him from his enemy.
And it is also written: 'Present it now to your governor, etc.' Our ancestors also had this practice when the king would come to a province, they would slaughter a bull before him, and they would take the blood of the bull from the community chest. And no one raised any objection to this due to idolatry, because their intention was not to serve him or accept him as a deity. It was only a sign of honor they accorded him.
Our forefather Jacob said to his sons: 'Take some of the best products of the land in your vessels and bring the man a gift, a little balsam and a little honey, etc.' And it states: 'And they brought him the gift which was in their hand, and they bowed down to him, etc.' But concerning Saul the chosen of the Lord, it is said: 'And the wicked sons said, "How can this man save us?" and they did not bring him a gift.'
In the Tractate Nedarim, we learned: 'One takes a vow concerning an offering, and he said, "I took a vow only concerning the offerings of kings."' This indicates that prostration, slaughter, offering of gifts, and all four internal acts of service are permitted for a person who is not worshipped like Haman, for if he is worshipped like Haman, it is forbidden. Thus, Mordecai refrained from prostrating before Haman because he made himself an object of worship.