"In returning and rest you shall be saved; in quietness and confidence shall be your strength" (Isa. 30:15). We find the Scriptures instructing us to, "have no confidence in the flesh" (Phil. 3:3). Notice the simplicity and clarity of this teaching: "have no confidence in the flesh." This teaching allows for no exceptions whatever! "No" means no. The most dangerous flesh to have confidence in is our own.
Many today worry about their financial situations and at the same time say they believe the Word of God. Their worry and anxiety belays their unbelief and lack of confidence in God and they deny His power by their whining and complaining about what a sad lot their life has become.
Jesus is so basic and clear in Matthew 6:24-34 when He, The Creator, our Provider and Redeemer says calmly and quietly, "I say to you, do not worry. For after all these things the Gentiles [unbelievers] seek. Your heavenly Father knows that you need all these things, but seek first His kingdom and His righteousness and all these things will be added [given] to you."
If you cannot depend upon God to take care of you down here for a few short days, months, or years, do you expect Him to believe that you will know how trust Him to take care of you for eternity? What you do here, you will do there; what you are here, you will be there. Who you depend on here, you will depend on there (Rev. 22:11). "Abraham had such confidence in the life and power of the word of the Lord that he believed that it would fulfill itself." 
Lacking confidence and assurance in the Word of God, "many people hesitate to make a start to serve the Lord, because they fear that God will not accept them; and thousands who have been professed followers of Christ for years, still doubt their acceptance with God."  What they lack is simple faith that believes exactly what God says and expects His word to fulfill itself.
They ask, "Will the Lord receive me?"  I reply by another question: Will a man receive that which he has bought? Yes, of course he will! If he did not want them, he would not have bought them. Now let us apply this simple, natural illustration to the case of the sinner coming to Christ. In the first place, He has bought us. "Do you not know you're your body is the temple of the Holy Spirit who is in you, whom you have from God, and you are not your own? For you were bought at a price; therefore glorify God in your body and in your spirit, which are God's" (1 Cor. 6:19, 20).
He bought not a certain class, but the whole world of sinners. "For God so loved the world, that He gave His only begotten Son" (John 3:16). "This is indeed the Christ, the Savior of the whole world" (John 4:42; see also 1 Tim. 4:10).
The price that was paid for us was His own blood--His life. He "gave Himself for us" (Titus 2:14). He "gave Himself for our sins, that He might deliver us from this present evil age, according to the will of our God and Father" (Gal. 1:4). The price paid was infinite; therefore we know that He very much desired that which He bought. He had His heart set on obtaining it. He could not be satisfied without it (see Heb. 12:2; Isa. 53:11).
Yet, some drone on, "But I am not worthy."  That means that you are not worth the price paid, and therefore you fear to come lest Christ will refuse to accept what He purchased. The bargain Christ made for you has been sealed, and the price already paid!
Further, you have nothing to do with the question of worth. When Christ was on earth "He knew what was in man" (John 2:25). He made your purchase with His eyes wide open, and He knew the exact value of that which He bought. He is not at all disappointed when you come to Him and He finds that you are worthless. You are not to worry over the question of your worth; if He, with His perfect knowledge of your case, was satisfied to make the bargain, you should be the last one to complain.
Now, for the most wonderful truth of all: He bought you for the very reason that you are not worthy. He did not buy you for what you were or are now worth, but for what He could make of you. He says: "I, even I, am He who blots out your transgressions for My own sake" (Isa. 43:25). We have no righteousness.
Surely all doubt as to acceptance with God ought to be set at rest. But it is not. The evil heart of unbelief still suggests doubts. If we believe in a God that made heaven and earth, and that still upholds all things by the word of His power, why do we not trust Him to take care of us, and to protect us?
Paul asked God three times that the "thorn in the flesh" that he carried might be removed from him. The Lord answered him saying, "My grace is sufficient for you, for my strength is made perfect in weakness."
Is God's grace sufficient for us today? Is His grace sufficient to take care of you? Kneel before Him and ask Him to humble you from your pride and self-sufficiency. His grace is more than enough.
As to your being Christ's, you can settle that yourself. You have seen what He gave for you. Now the question is, "Have you delivered yourself to Him?" He begs you to give Him that which He has bought and paid for.
 Ellet J. Waggoner, The Everlasting Covenant, Chapt. 9, "The Test of Faith", July 2, 1896.
 Waggoner, "Acceptance with God," The Present Truth, July 1, 1897.