'Solemnly' in the Bible

Bring all this to men's remembrances, solemnly charging them in the presence of God not to waste time in wrangling about mere words, a course which is altogether unprofitable and tends only to the ruin of the hearers.

I solemnly implore you, in the presence of God and of Christ Jesus who is about to judge the living and the dead, and by His Appearing and His Kingship: