The phrase 'A Bird in the Hand is Worth Two in the Bush' is used for saying that it's better to hold onto something one has already than to risk losing it by trying to attain something better.
Though the origin of the idiom 'a bird in the hand is worth two in the bush' isn’t exactly known, what is known is that this is a very old saying. There are various examples of the idiom appearing in early print dating back to the 16th century; one 1530 statement by Hugh Rhodes reads “Better one byrde in hande than ten in the wood.”