St Jude is one of those saints Catholicism ‘does’ rather well. Although his identity is matter for conjecture (not his existence, his identity— see here, for example), he has been adopted as the patron saint of hopeless or lost causes. There is an old prayer which runs
O most holy apostle, Saint Jude, faithful servant and friend of Jesus, the Church honours and invokes you universally, as the patron of hopeless causes, and of things almost despaired of. Pray for me, who am so miserable. Make use, I implore you, of that particular privilege accorded to you, to bring visible and speedy help where help was almost despaired of. Come to my assistance in this great need, that I may receive the consolation and succour of heaven in all my necessities, tribulations, and sufferings, particularly (here make your request) and that I may praise God with you and all the elect throughout eternity. I promise you, O blessed Jude, to be ever mindful of this great favour, always to honour you as my special and powerful patron, and gratefully to encourage devotion to you. Amen.
That prayer expresses the comfortable familiarity Catholicism has with her saints; her honouring them first and foremost as servants and friends of Christ; her confidence that they will interest themselves in our affairs; and her conviction that nothing is too unimportant or ‘hopeless’ to be brought before God. St Benedict was well aware that impossible things can sometimes be asked of us (he devotes a whole chapter of his Rule to the subject), but devotion to St Jude takes that awareness one step further. In asking the prayers of St Jude, we acknowledge not only our creatureliness, but also our tendency to lose hope, to despair. St Benedict may exhort us, as the last and greatest of the tools of good works, never to despair of God’s mercy (RB 4.74), but St Jude is there for when we tremble on the brink of doing so. He is a good saint to have in our armoury of prayer.