Most churches will celebrate Palm Sunday today in some fashion. In some traditions, the celebration, perhaps beginning with All glory, laud, and honor in a procession, extends through the whole service, the Gospel reading tells of Jesus' triumphant entry into Jerusalem, and the final hymn is still something joyful like Hosanna, loud hosanna.
In other places, the reading of the Passion story occurs at some point during the service, changing the emphasis from celebration to suffering. The end of the service will be more somber, including something like O sacred head. One argument for this seems to be that people today are less likely to come to church on Maundy Thursday and Good Friday, so they should hear the story on a Sunday morning (and some churches don't even have services on both or either of those days, let alone on Holy Saturday). There is some resistance to the idea of leaving the palms aside for the Passion, though there also may well be those in the all-celebration mode who would like a little more of the upcoming suffering acknowledged.
Today's hymn, perhaps more appropriate for the second sort of Palm/Passion Sunday, not only looks forward to the sadness of the coming week, but also to the final triumph of Easter. It's by John Mason Neale, first published in his Hymns for Children (1842) and one of his original texts (which are far outnumbered by his translations from older sources).
O Christ, who through this holy week
Didst suffer for us all,
The sick to heal, the lost to seek,
To raise up them that fall;
We cannot tell the bitter woe
Thy love was pleased to bear;
O Lamb of God, we only know
That all our hopes are there.
Thy feet the path of suff'ring trod,
Thy hands the victory won;
What shall we render to our God
For all God's mercies done.
O grant us, Christ, at Easter day
With thee to rise anew;
Then at the last, to soar away,
And heav'nly life pursue.
To God, the blessed Three in One
All praise and glory be!
Crown, Lord, thy people who have won
Through thee, the victory.
John Mason Neale, 1842; alt.
Tune: ST. MAGNUS (C.M.)
Jeremiah Clarke, 1707; harm. William H. Monk, 1868
P.S. - Best hashtag seen for the day: #Special Fronds
Eight (Liturgical) Years Ago: Green Palms and Blossoms Gay
Seven (Liturgical) Years Ago: Hosanna, loud hosanna
Six (Liturgical) Years Ago: Ride on, ride on in majesty
Five (Liturgical) Years Ago: Come, faithful people, come away
Four (Liturgical) Years Ago: See what unbounded zeal and love
Five (Calendar) Years Ago: May Whittle Moody