Why is the concept of 'shall' vital in biblical prophecy?

The usage of 'shall' in Scripture, particularly in prophetic contexts like in Obadiah 1:17, underscores God's sovereign decree and certainty. When God declares 'it shall be,' it indicates a completed action that is inherent in His divine will. Unlike the word 'will,' which can imply potential or future action, 'shall' asserts a definitive outcome rooted in God’s eternal plan. As believers, this gives us immense comfort and assurance that the promises of God are not mere possibilities but certainties that will come to fruition. Each 'shall' resonates with the premise that God's purposes are unshakeable, reinforcing our faith as we navigate through trials, knowing that what He has declared will indeed come to pass.