Tribulation which produces endurance is useful; it leads to glory. I am with him in trouble, he says, I will rescue him and glorify him. Let us give thanks to the Father of mercies who is with us in tribulation and consoles us in all our tribulations. …. The hope of glory lies in tribulation, and surely glory itself is contained within that same tribulation, just as the hope for the fruit lies in the seed, and as the fruit itself is in the seed. In this way too the kingdom of God is now within us, a treasure in a clay vessel, in a worthless field. It is there, I tell you, but it is hidden. Happy is the person who shall find it. Who is he? Surely it is he who gives more thought to the harvest than to the sowing. … It is good for me to be troubled, Lord, as long as you are with me, better than reigning without you, of feasting without you, of being glorified without you. It is good for me to embrace you in tribulation, to have you with me in the furnace, better than being without you even in heaven.
Bernard of Clairvaux, Lenten Sermons on the Psalm ‘He Who Dwells’ , Sermon Seventeen: On the Sixteenth Verse – “With the length of days shall I satisfy him and show him my salvation” v. 3, 4 (CF 25, p 255-7)