Now I pray to God that you do no evil, not that we should appear approved, but that you should do what is honorable, though we may seem disqualified. – 2 Corinthians 13:7

Take it for granted, dear friends, as a truth which your own observation and experience will make every day more and more clear, that your power to spread religion in the world must mainly depend upon your own personal character, of course, in absolute reliance upon the Holy Spirit. I suppose it is the earnest wish of every Christian to win for Christ some new converts, to bring some fresh province under the dominion of the King of kings.

Your power to achieve this noble purpose must largely depend upon your own personal consistency. It little availeth what I say if I do the reverse. The world will not care about my testimony with the lip, unless there be also a testimony in my daily life for God, for truth, for holiness, for everything that is honest, lovely, pure, and of good report. There is that in a Christian’s character which the world, though it may persecute the man himself, learns to value. It is called consistency, that is, the making of the life stand together, not being one thing in one place and another thing in another, or one thing at one time and quite different on another occasion. It is not consistency to be devout on Sunday and to be dishonest on Monday. It is not consistency to sing the songs of Zion to-day, and to shout the songs of lustful mirth tomorrow. It is not consistency occasionally to wear the yoke of Christ, and yet frequently to make yourself the serf of Satan. But to make your life all of a piece is to make it powerful, and when God the Holy Ghost enables you to do this, then your testimony will tell upon those amongst whom you live. It would be ludicrous, if it were not so sorrowful a thing, to be spoken of even with weeping, that there should be professed Christians who are through inconsistency among the worst enemies of the cross of Christ… If your life be not all of a piece, the world will soon learn how to estimate your testimony, and will count you to be either a fool or a knave, and perhaps both. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/2469.cfm