Halakhah к Шофтим 3:20

Some authorities maintain that you are not required to stand during Kaddish. But, if you are already standing when Kaddish is to be said for instance, after Halleil,¹⁵And one is required to stand during Halleil. you should remain standing until after: Amein, yehei shemei rabba. Others hold the opinion that you should always stand during Kaddish as well as during other prayers of Kedushah.¹⁶E.g., Barechu or Kedushah of Shemoneh Esrei. This can be derived by means of a kal v'chomer¹⁷Kal vachomer—if a strict rule applies to a lenient law, then it certainly applies to a stringent law. The converse is also true—if a lenient rule applies to a strict law, then it certainly applies to a lenient law. from the case of Eglon, king of Moab, for it is written:¹⁸Judges 3:20. "Ehud came to him etc. and Ehud said: 'I have brought you a word of God. ' And he (Eglon) stood up from his throne."¹⁹Thus, we see that Eglon rose to hear the word of God. If Eglon King of Moab, who was an idol worshipper, rose [to hear] the word of God, how much more so, [should] we, who are His people. Therefore, it is preferable to be stringent.