James 4:13-16 Semi-Paraphrased
Come now you who [make your own plans], yet you do not know what tomorrow will bring... Instead you ought to say, "If it is the Lord's will, we will live and do this and that." As it is, you boast in your arrogance and that is evil.
Many are the plans in the minds of a man, but it is the purpose of the Lord that will stand.
So it depends not on human will or exertion but on the Lord who has mercy.
And the Clincher: Jeremiah 29:11
For I know the plans I have for you declares the Lord, plans to prosper you not to harm you, plans to give you a hope and a future.