We don’t know what tomorrow may bring. But we say, what we’re going to do, as though tomorrow is guaranteed.
You should say; “if it be thy will, I will do ____”.
Proverbs 27:1 (KJV) – boast not thyself of to morrow; for thou knowest no what a day may bring forth.
I Peter 4:15 (KJV) – for that ye ought to say, If the Lord will, we shall live, and do this, or that.