Westminster Q81: Are all true believers at all times assured of their present being in the estate of grace, and that they shall be saved?

(Eph 1:13) In Him, you also, after listening to the message of truth, the gospel of your salvation--having also believed, you were sealed in Him with the Holy Spirit of promise,
(Isa 1:10) Hear the word of the LORD, You rulers of Sodom; Give ear to the instruction of our God, You people of Gomorrah.

(Psa 88:1-3, 6-7, 9-10, 13-15) . . . O LORD, the God of my salvation, I have cried out by day and in the night before You. Let my prayer come before You; Incline Your ear to my cry! For my soul has had enough troubles, And my life has drawn near to Sheol. . . You have put me in the lowest pit, In dark places, in the depths. Your wrath has rested upon me, And You have afflicted me with all Your waves. Selah. . . My eye has wasted away because of affliction; I have called upon You every day, O LORD; I have spread out my hands to You. Will You perform wonders for the dead? Will the departed spirits rise and praise You? Selah. . . But I, O LORD, have cried out to You for help, And in the morning my prayer comes before You. O LORD, why do You reject my soul? Why do You hide Your face from me? I was afflicted and about to die from my youth on; I suffer Your terrors; I am overcome.
(Psa 22:1) . . . My God, my God, why have You forsaken me? Far from my deliverance are the words of my groaning.

(Psa 31:22) As for me, I said in my alarm, "I am cut off from before Your eyes"; Nevertheless You heard the voice of my supplications When I cried to You.

(Psa 51:8, 12) Make me to hear joy and gladness, Let the bones which You have broken rejoice. . . Restore to me the joy of Your salvation And sustain me with a willing spirit.

(Psa 77:1-12) . . . My voice rises to God, and I will cry aloud; My voice rises to God, and He will hear me. In the day of my trouble I sought the Lord; In the night my hand was stretched out without weariness; My soul refused to be comforted. When I remember God, then I am disturbed; When I sigh, then my spirit grows faint. Selah. You have held my eyelids open; I am so troubled that I cannot speak. I have considered the days of old, The years of long ago. I will remember my song in the night; I will meditate with my heart, And my spirit ponders: Will the Lord reject forever? And will He never be favorable again? Has His lovingkindness ceased forever? Has His promise come to an end forever? Has God forgotten to be gracious, Or has He in anger withdrawn His compassion? Selah. Then I said, "It is my grief, That the right hand of the Most High has changed." I shall remember the deeds of the LORD; Surely I will remember Your wonders of old. I will meditate on all Your work And muse on Your deeds.
(1Jn 3:9) No one who is born of God practices sin, because His seed abides in him; and he cannot sin, because he is born of God.

(Job 13:15) "Though He slay me, I will hope in Him. Nevertheless I will argue my ways before Him.

(Psa 73:15, 23) If I had said, "I will speak thus," Behold, I would have betrayed the generation of Your children. . . Nevertheless I am continually with You; You have taken hold of my right hand.

(Isa 54:7-10) "For a brief moment I forsook you, But with great compassion I will gather you. "In an outburst of anger I hid My face from you for a moment, But with everlasting lovingkindness I will have compassion on you," Says the LORD your Redeemer. "For this is like the days of Noah to Me, When I swore that the waters of Noah Would not flood the earth again; So I have sworn that I will not be angry with you Nor will I rebuke you. "For the mountains may be removed and the hills may shake, But My lovingkindness will not be removed from you, And My covenant of peace will not be shaken," Says the LORD who has compassion on you.