We can come to Jesus in full assurance that He will do all that He has promised. Reference: E.G. White, "The Upward Look," p. 320.

Full text of the devotional: “Blessed Assurance,” November 2

I will never leave thee, nor forsake thee. Hebrews 13:5.

We have but one life to live, and through our daily connection with God we have, in and through the merits of the Lord Jesus Christ, a constant sustenance in doing the things that will represent Christ to the world. We may not have all the conveniences that some have in ease and comfort and in earthly goods, but we have the blessed assurance which Christ gave to His believing disciples... To them He said, “Let not your heart be troubled: ye believe in God, believe also in me. In my Father’s house are many mansions: if it were not so, I would have told you. I go to prepare a place for you. And if I go and prepare a place for you, I will come again, and receive you unto myself; that where I am, there ye may be also” (John 14:1-3)...

Blessed words! We may receive Him into our hearts, and He will be unto us hope and courage and sustaining grace. The Lord would have us trust fully and entirely in Him. Then we will, in the simplicity of our faith, believe that Christ will do for us all that He has promised. Let all come to the Saviour in the full assurance that He will do all that He has promised.

We cannot please our Saviour more than by having faith in His promises. His mercies can come to you, and your prayers can come to Him. Nothing can break this line of communication. We must learn to bring all perplexities to Jesus Christ, for He will help us. He will listen to our requests. We may come to Him in full assurance of faith, nothing doubting, for He is the living Way...

The more we press our petitions to His throne, the more sure we are of constantly receiving the great grace of our Lord Jesus Christ. You do not give strength to the road you are traveling by [having] faith. But you increase in strength and in assurance because you have a Guide right by your side, and you can ask Him with perfect faith to guide your steps aright.

Then trust in the Lord Jesus to lead you step by step into the right path. You can derive assurance and strength at every step you advance, for you can be assured that your hand is in His hand. You can “run and not be weary”; you can “walk and not faint,” for you can realize by faith that you have your hand in the hand of Christ. You will not sink under discouragement, for as you follow on to know the Lord, trusting in Him, you will have the assurance that the One who never forsakes those who fully trust Him is your constant Helper.—Letter 313, November 2, 1905, to Mabel White, her 19-year-old granddaughter.