The closest I could find in the OED2 is this definition and citation:
† 3. An act of rendering (thanks). Obs. rare-1.
- 1594 in Cath. Rec. Soc. Publ. V. 283
To give to his temporal benefactors a sweet surrender of thanks.
But I’m not sure that this is the operative definition.
First, it isn’t all that rare, although it does sound a bit lyrical. It appears in several recent songs. “Sweet Surrender” is a song written by David Gates and performed by Bread, and which hit the #1 slot. It is also the title of a completely different song by Sarah McLachlan, with its own lyrics and tune. So, too, did John Denver, which is the tune that comes to my mind when I hear the “sweet surrender”.
This page quotes Eckhart Tolle from The Power of Now, giving probably the best explanation of this use of the word:
“To some people, surrender may have negative connotations, implying defeat, giving up, failing to rise to the challenges of life, becoming lethargic, and so on. True surrender, however, is something entirely different. It does not mean to passively put up with whatever situation you find yourself in and to do nothing about it. Nor does it mean to cease making plans or initiating positive action.
“Surrender is the simple but profound wisdom of yielding to rather than opposing the flow of life. The only place where you can experience the flow of life is the Now, so to surrender is to accept the present moment unconditionally and without reservation. It is to relinquish inner resistance to what is.”
It then goes on to list several other songs that use the phrase:
- Sweet Surrender – John Denver
- Surrendering – Alanis Morissette
- Sweet Surrender – Bread
- Surrender – Cheap Trick
- Sweet Surrender – Sarah McLachlan
- Your Surrender – Neon Trees
- Moment of Surrender – U2
- Surrender – The Presets
But second, let me emphasize that this is a positive kind of thing, not a negative one. The normal sense of surrender is the OED’s sense 2:
- 2. The giving up of something (or of oneself) into the possession or power of another who has or is held to have a claim to it; esp. (Mil., etc.) of combatants, a town, territory, etc. to an enemy or a superior. In wider sense: Giving up, resignation, abandonment.
Instead of being negative as surrender itself normally is, sweet surrender is laying down one’s cares, abandoning all strife and resistance. Whether it is truly “thankful” per the OED2’s definition 3 with the obelus above, I am uncertain. I think perhaps they are just missing out of what sweet surrender really means.