You can find a YouTube playlist here with many of the songs suggested below.
For setting up the Trinity theme the classic opener would be Holy, holy, holy, Lord God almighty (CH 111 / MP 237) which can be accompanied in a whole range of styles and instrumentation and also picks up on words from Isaiah, as does Glory be to God the Father (CH 110). Today I awake (CH 211) explores our relationship with each member of the Trinity and has some wonderful imagery with a tune that is well worth learning while Source and Sovereign, Rock and Cloud (CH 133) does the incredible task of giving twelve names for each member of the Trinity set to the majestic tune Aberystwyth. Our God saves (CCLI / MP 1192) is explicitly Trinitarian in the way few songs of its style are while In the name of God the Father (Resound) is a less well known song which also does this. Looking at shorter songs Jesus lead us to the Father (Resound) is fast becoming a modern classic which can simply be sung in unison but when used as a round can really build a wonderful time of praise while This is the day (CH 194 / MP 691) has various versions but would work for this day if you use the version with the verses “This is the day… that the Lord has made / the he rose again / when the Spirit came”.
Interestingly there are two paraphrases of Psalm 29 from different sources both set to the tune Ebenezer, All who throng the halls of heaven (WGRG) and All on earth and all in heaven (PFAS 29A), with the strength of this tune a good match for the text with its imagery of thunder, trembling and tumult.. Ascribe unto the Lord (Grace) is set to a Sacred Harp tune and would be well suited to a folky arrangement by a band. Ascribe (CCLI) takes the first few verses as its starting point and while it is probably more suited to a solo voice it’s simple enough for a congregation to pick up with some sections that can be repeated. The earth is yours (CCLI) focuses on the verses about the “voice of the Lord” and how creation responds and is also written more with a solo voice but a congregation could at least pick up the chorus.
There are some general Trinitarian songs which might be useful for this week such as O threefold God of tender unity (CH 114), Loving Creator (CH 116), Trinity song (CCLI) and Mothering God, you gave me birth (CH 117 / Wild Goose), the latter based on a text by Julian of Norwich, something worth remembering when people say feminine imagery for God is a modern invention.
There is a huge amount packed into the Gospel passage and many different approaches to it so it’s only possible to suggest a few highlights here. The kingdom of God (Taizé) would link to the early part of the passage while some songs suggested last week for Pentecost such as Spirit of the living God (CH 619 / MP 613), Gracious Spirit, hear our pleading (CH 613), Holy Spirit, living breath of God (MP 1183 / CCLI / Getty) or Fresh wind (CCLI) could tie in with the the Spirit focus. Perhaps unsurprisingly there are a lot of songs directly inspired by John 3:16, although the most famous is probably the choral setting by Stainer (Hymnary). The short chant God so loved the world (link) is set to music from Beethoven’s “Pathétique Sonata”, while God so loved (CCLI) and God so loved the world (Common) are more recent worship songs. God loved the world so much (WGRG recording and lyrics) is set to the tune Wondrous Love and has a real strength when sung unaccompanied.
Angel voices ever singing (CH 498 / MP 34) would tie in with the Old Testament reading with our response to the angels’ song of praise being to offer ourselves to God. For a more explicit focus on Isaiah’s vision you could consider the Victorian hymn Bright the vision that delighted (NEH 343) or the Rwandan song Heaven opened to Isaiah (GSW 6) while Sweetest mystery (Gordon) is a reflection on both Isaiah 6 and the Trinity so very appropriate for this week. There are also many options for singing the words of the seraphim including the wonderful MacMillan setting of the Sanctus (St Anne Mass) (CH 651), the Argentianian Santo, santo, santo / Holy, Holy, holy (CH 769), or Nathan Fellingham’s Holy, holy (MP 1058 / CCLI). Finally, I, the Lord of sea and sky (CH 251) would link with Isaiah’s response to God.
Some of the songs suggested for the Gospel above could also link in with the theme of being led by the Spirit we find in the Epistle. The other strong theme here is about being children of God where you could consider songs such as I am a child of God (MV 157), Behold the amazing gift of love (CH 478), Who you say we are (CCLI) and Children of God (CCLI). Loving Creator, grant to your children (CH 116) also picks up this theme and the Trinitarian structure of the verses would tie nicely into the season.
There are some wonderful Trinitarian hymns set to older tunes which can provide a suitably heightened conclusion such as I bind unto myself today (CH 639) or God, whose almighty word (CH 112). This is a more challenging theme to find in well-known contemporary songs but is picked up in How great is our God (CCLI / MP 1227) which is often followed with a chorus of How great thou art (CH 154 / MP 506).
You could also link with the end of Isaiah through songs where we respond to God’s call to mission. I, the Lord of sea and sky (CH 251) would be an obvious option if you haven’t already used it while For my sake and the gospel’s, go (CH 248) appropriately finishes with praise to the Triune God. Some other options could be Mission’s Flame (CCLI), Sent by the Lord am I (CH 250) or Murassala (WGRG / H 82), a wonderful song from South Sudan which calls on us all to be ambassadors of Jesus.