Both my DSs have been attending church and children's clubs at the Salvation Army. Although DH and I are not particularly religious, we felt Sunday School etc was an important part of their upbringing and would enable them to make their own decisions. I fully support the work of the Salvation Army and am involved myself with fundraising etc.
DS1 has never really "believed" but DS2 does (8yo) and wants to become a junior soldier. I support this as part of him exploring all things spiritual, but it will mean him making this promise
I do genuinely think he understands the first part about Jesus, but I don't see how he can pledge now never to touch alcohol etc, when he's never experienced it.
Does it matter if he makes the promise anyway? I'm concerned that I might be setting him up for a life of guilt when (realistically) he does start drinking. We do drink in moderation occasionally at home and have no plans to change that.