He who began a good work in you will complete it until the day of Jesus Christ.
If we are faithless, He remains faithful, for He cannot deny Himself.
Faithful is He who calls you and He also will bring it to pass.
The God of peace will Himself sanctify you entirely; and will preserve your spirit and soul and body complete, without blame at the coming of our Lord Jesus Christ.
But the Lord is faithful; He will strengthen you and protect you from The Evil One.
He will not always chide, neither will He keep His anger forever.
God is faithful, through whom you were called into fellowship with His Son, Jesus Christ.
Let us hold unswervingly to the hope we profess, because He who promised is faithful.
And the God of all grace, who called you to His eternal glory in Christ, after you have suffered a little while, will Himself restore you and make you strong, firm, and steadfast.
Know therefore that the Lord, He is God, the faithful God, keeping His covenant of love to a thousand generations of those who love Him and keep His commandments.
His compassions fail not, they are new every morning. Great is Thy faithfulness.
From A.W. Pink:
God is true. His Word of Promise is sure. In all His relations with His people God is faithful. He may be safely relied upon. No one ever yet really trusted Him in vain. We find this precious truth expressed almost everywhere in the Scriptures, for His people need to know that faithfulness is an essential part of the Divine character. This is the basis of our confidence in Him. But it is one thing to accept the faithfulness of God as a Divine truth, it is quite another to act upon it. God has given us many "exceeding great and precious promises," but are we really counting on His fulfillment of them? Are we actually expecting Him to do for us all that He has said? Are we resting with implicit assurance on these words, "He is faithful that promised" (Heb. 10:23)? There are seasons in the lives of all when it is not easy, no not even for Christians, to believe that God is faithful. Our faith is sorely tried, our eyes bedimmed with tears, and we can no longer trace the outworkings of His love. Our ears are distracted with the noises of the world, harassed by the atheistic whisperings of Satan, and we can no longer hear the sweet accents of His still small voice. Cherished plans have been thwarted, friends on whom we relied have failed us, a professing brother or sister in Christ has betrayed us. We are staggered. We sought to be faithful to God, and now a dark cloud hides Him from us. We find it difficult, yea, impossible, for carnal reason to harmonize His frowning providence with His gracious promises. Ah, faltering soul, severely-tried fellow-pilgrim, seek grace to heed Isaiah 50:10, "Who is among you that feareth the Lord, that obeyeth the voice of His servant, that walketh in darkness and hath no light? let him trust in the name of the Lord, and stay upon his God."
When you are tempted to doubt the faithfulness of God, cry out, "Get thee hence, Satan." Though you cannot now harmonize God’s mysterious dealings with the avowals of His love, wait on Him for more light. In His own good time He will make it plain to you. "What I do thou knowest not now, but thou shalt know hereafter" (John 13:7). The sequel will yet demonstrate that God has neither forsaken nor deceived His child. "And therefore will the Lord wait that He may be gracious unto you, and therefore will He be exalted, that He may have mercy upon you: for the Lord is a God of judgment: blessed are all they that wait for Him" (Isa. 30:18).
Judge not the Lord by feeble sense,
But trust Him for His grace,
Behind a frowning providence
He hides a smiling face.
Ye fearful saints fresh courage take,
The clouds ye so much dread,
Are rich with mercy, and shall break
In blessing o'er your head.