'Firmly' in the Bible

He answered, “Because of your little faith [your lack of trust and confidence in the power of God]; for I assure you and most solemnly say to you, if you have [living] faith the size of a mustard seed, you will say to this mountain, ‘Move from here to there,’ and [if it is God’s will] it will move; and nothing will be impossible for you.

and said, ‘For this reason a man shall leave his father and mother and shall be joined inseparably to his wife, and the two shall become one flesh’?