This is very good advice! We live in extremely dangerous times! Obviously, the sign quotes The Apostle Paul and is two thousand years old, but is still relevant today. At this point, I think it would be beneficial to put the above quote in context. Read on...
Ephesians, Chapter 5 (WEB)
1 Be therefore imitators of God, as beloved children. 2 Walk in love, even as Christ also loved you, and gave himself up for us, an offering and a sacrifice to God for a sweet-smelling fragrance. 3 But sexual immorality, and all uncleanness, or covetousness, let it not even be mentioned among you, as becomes saints; 4 nor filthiness, nor foolish talking, nor jesting, which are not appropriate; but rather giving of thanks.
5 Know this for sure, that no sexually immoral person, nor unclean person, nor covetous man, who is an idolater, has any inheritance in the Kingdom of Christ and God.
6 Let no one deceive you with empty words. For because of these things, the wrath of God comes on the children of disobedience. 7 Therefore don’t be partakers with them. 8 For you were once darkness, but are now light in the Lord. Walk as children of light, 9 for the fruit of the Spirit is in all goodness and righteousness and truth, 10 proving what is well pleasing to the Lord. 11 Have no fellowship with the unfruitful works of darkness, but rather even reprove them. 12 For the things which are done by them in secret, it is a shame even to speak of. 13 But all things, when they are reproved, are revealed by the light, for everything that reveals is light. 14 Therefore he says, “Awake, you who sleep, and arise from the dead, and Christ will shine on you.”
15 Therefore watch carefully how you walk, not as unwise, but as wise; 16 redeeming the time, because the days are evil. (emp. added GDR) 17 Therefore don’t be foolish, but understand what the will of the Lord is.
Christians are meant to be an unusual people. We can't do all the things the world does and therefore it is normal that some will hate us. It is plain to me that persecution will ultimately follow, but Christians of the 1st century overcame opposition and severe persecution and so can we!! Follow God and not what our culture says is OK. Remember, the reward is eternal fellowship with God in heaven.
I'll bet you will be glad you paid attention to the sign!!!
ps. A word of encouragement to our brethren in Russia: Even though the government is trying to limit the practice of your faith, God will help you to spread the GOSPEL!!! Stand strong!!!!