Joshua 2:12

2:12 So now, promise me this with an oath sworn in the Lord’s name. Because I have shown allegiance to you, show allegiance to my family. Give me a solemn pledge

Joshua 14:9

14:9 That day Moses made this solemn promise: ‘Surely the land on which you walked will belong to you and your descendants permanently, for you remained loyal to the Lord your God.’

Joshua 23:7

23:7 or associate with these nations that remain near you. You must not invoke or make solemn declarations by the names of their gods! You must not worship or bow down to them!