Following are a number of back-translations as well as a sample translation for translators of Isaiah 30:15:

• Kupsabiny: “The God if Israel is saying
  the one who is righteous,
  ‘If you would repent and lean on me
  I would save you.
  If you trust in me
  you get strength and will be in peace.’
  But you did not accept to do like that.” (Source: Kupsabiny Back Translation)
• Newari: “The LORD God, the Holy God of Israel, has spoken like this,
  "You salvation is in repentance and rest.
  Your strength will be in trusting and meditation.
  But you also had no liking for any of these matters.” (Source: Newari Back Translation)
• Hiligaynon: “The Lord GOD, the Holy of God of Israel still says, ‘You (plur.) return to me and relax for I will-save you (plur.). You (plur.) be-at-peace and trust in me for I will-strengthen you (plur.). But you (plur.) do- not -want to do it.” (Source: Hiligaynon Back Translation)
• English: “Yahweh, our God, the Holy One of Israel, also says this:
  ‘You will be rescued from your enemies only if you repent and trust in what I will do for you;
  you will be strong only if you quit worrying and trust in me.
  But you do not want to do that.” (Source: Translation for Translators)