Be sure to guard in your heart the joy of the Holy Spirit, and do not allow the evil one to pour out his bitterness. Beware! Beware, lest the Paradise that exists in you turns into Hell. Nectarios of Aegina
Make yourself an honest man, and then you may be sure that there is one less scoundrel in the world. Thomas Carlyle
If one way be better than another, that you may be sure is nature's way. Aristotle
When you see gossamer flying, be sure the air is drying. American Proverb
If you turn into a dog, be sure to choose a rich family. Japanese Proverb
Better be sure than sorry. Irish Proverb