Is your salvation secure and sure to the end? Hebrews 5-7

Hebrews 6:17-19 (NASBStr)

In the same way God, desiring even more to show to the heirs of the promise the unchangeableness of His purpose, interposed with an oath, so that by two unchangeable things in which it is impossible for God to lie, we who have taken refuge would have strong encouragement to take hold of the hope set before us. This hope we have as an anchor of the soul, a hope both sure and steadfast and one which enters within the veil,

Now that is a mouth full!!  If you read the above passage in Hebrews you might easily get confused with the writer's language.   If we read the same passage in the Amplified Bible version we get a long rendition of it, but perhaps might grasp the writer's meaning more readily:

Hebrews 6:17-19 (AMP)

Accordingly God also, in His desire to show more convincingly and beyond doubt to those who were to inherit the promise the unchangeableness of His purpose and plan, intervened (mediated) with an oath.

 This was so that, by two unchangeable things [His promise and His oath] in which it is impossible for God ever to prove false or deceive us, we who have fled [to Him] for refuge might have mighty indwelling strength and strong encouragement to grasp and hold fast the hope appointed for us and set before [us].

 [Now] we have this [hope] as a sure and steadfast anchor of the soul [it cannot slip and it cannot break down under whoever steps out upon it—a hope] that reaches farther and enters into [the very certainty of the Presence] within the veil,

The key to the passage is that the believer's assurance is based upon the promises and oath of God's Word, that never changes and never fails.  This might come strange to us as there is nothing comparable for us to relate to.  Nothing in our life can compare to the assurance we have in the God's promises, oath and non-changing of His plan.   When God says we have an anchor, the metaphor of the ship not moving because the anchor is set in the rocks at the bottom of the sea, He gives us a powerful picture.   We don't have to worry about our salvation.  It is strong and sure, like an anchor for our ship.   God will get us to the end of our salvation and therefore we must believe to the end (the main theme of Hebrews).  If you have ever had a time  you doubted your salvation or God's ability to save you completely because of your constant sin, God is there, as an anchor to your soul.