'Solemn' in the Bible

"I tell you in solemn truth," He added, "that no Prophet is welcomed among his own people.

Blessed are those servants, whom their Master when He comes shall find on the watch. I tell you in solemn truth, that He will tie an apron round Him, and will bid them recline at table while He comes and waits on them.

I tell you in solemn truth that, whoever does not receive the Kingdom of God like a little child will certainly not enter it."

I tell you in solemn truth that the present generation will certainly not pass away without all these things having first taken place.

"I tell you in solemn truth," replied Jesus, "that this very day you shall be with me in Paradise."