St Thomas Aquinas and His Contribution to Adoration of the Blessed Sacrament
Here are the 5th and 6th verses in Latin:
O salutaris hostia, Quæ cæli pandis ostium, Bella premunt hostilia, Da robur, fer auxilium.
Uni trinoque Domino. Sit sempiterna gloria. Qui vitam sine termino. Nobis donet in patria.
English:
O saving Victim, opening wide, The gates of heaven to man below; Our foes press hard on every side, Thine aid supply, Thy strength bestow.
All praise and thanks to thee ascend, For evermore, blessed One in Three; O grant us life that shall not end, In our true native land with Thee.
To learn more about the philosophy of St. Thomas Aquinas you can refer to Aquinas’s Shorter Summa.