Pseudo-Jerome
Catena Aurea · Markusevangelium 14
And when they had sung an hymn, they went out into the mount of Olives. And Jesus saith unto them, All ye shall be offended because of me this night: for it is written, I will smite the shepherd, and the sheep shall be scattered. But after that I am risen, I will go before you into Galilee. But Peter said unto him, Although all shall be offended, yet will not I. And Jesus saith unto him, Verily I say unto thee, That this day, even in this night, before the cock crow twice, thou shalt deny me thrice. But he spake the more vehemently, If I should die with thee, I will not deny thee in any wise. Likewise also said they all.
For by a hymn he means the praise of the Lord, as is said in the Psalms, The poor shall eat and be satisfied; they that seek after the Lord shall praise him. (Ps. 22:26, 29) And again, All such as be fat upon earth have eaten and worshipped.