Keep preaching the truth, even when few will listen.
Noah was not only a builder. He was a preacher of righteousness.
2 Peter 2:5 (KJV): And spared not the old world, but saved Noah the eighth person, a preacher of righteousness, bringing in the flood upon the world of the ungodly;
Only eight souls went into the ark. Few listened, but he preached anyway.
1 Peter 3:20-21 (KJV): Which sometime were disobedient, when once the longsuffering of God waited in the days of Noah, while the ark was a preparing, wherein few, that is, eight souls were saved by water. The like figure whereunto even baptism doth also now save us (not the putting away of the filth of the flesh, but the answer of a good conscience toward God,) by the resurrection of Jesus Christ:
We are called to preach the Word in season and out of season.
2 Timothy 4:2 (KJV): Preach the word; be instant in season, out of season; reprove, rebuke, exhort with all longsuffering and doctrine.
Don't grow weary. God sees the work even when the crowd does not.
Galatians 6:9 (KJV): And let us not be weary in well doing: for in due season we shall reap, if we faint not.