St. Francis was surely borrowing from imagery as ancient as King David's Psalms when he wrote his song of praise, the Canticle of the Sun. In studying the Greek, there are some interesting parallels between the Beatitudes, declared by Christ in his sermon on the mount, (Matthew 5:3-12) and St. Francis' Canticle. I used to think the Beatitudes taught balance, or moderation. More study changed my opinion: a closer reading reveals extremes, not balance, and passion--not passivity. Brothers Wind and Fire and Sisters Water and Earth are also apparent in the Beatitudes, so here are the first four of Christ's Beatitudes juxtaposed with a section of the Canticle of St. Francis. Christ reveals here the spiritual effect of the lack of these four elements, while St. Francis celebrates their part in God's Creation. The paraphrasing of the Beatitudes that I have rendered here is intended to incorporate some of the nuances of the Greek text. Air, Water, Fire and Earth appear in the same order in both the Beatitudes and the Canticle--probably not coincidentally, the same order as in the Creation account in Genesis.
BEATITUDE: How enriched are those who pant and gasp for the breath of the spirit, for theirs are the vast winds of Heaven!
CANTICLE: Be praised, my Lord, through Brothers Wind and Air, and clouds and storms, and all the weather, through which you give your creatures sustenance.
BEATITUDE: How enriched are those who have watered their faces with tears while crying out, for they will be called to God's side!
CANTICLE: Be praised, My Lord, through Sister Water; she is very useful, and humble, and precious, and pure.
BEATITUDE: How enriched are those whose fever to acquire the stuff of earth has been quenched, for they will inherit the earth!
CANTICLE: Be praised, my Lord, through Brother Fire, through whom you brighten the night. He is beautiful and cheerful, and powerful and strong.
BEATITUDE: How enriched are those who are famished and ravenous to fulfull righteousness, for they will be satisfied!
CANTICLE: Be praised, my Lord, through our sister Mother Earth, who feeds us and rules us, and produces various fruits with colored flowers and herbs.