The word “become” (v.1) means fitting or appropriate. For example, women weren’t well received in Roman society, but Paul told the Romans that it isn’t fitting for God’s people not to receive a woman just because she’s a woman (Rom. 16:1,2).
“Become” also means to make something look good. The bickering in Philippi wasn’t making the gospel look good (Phil. 1:27). So when Paul told Titus to “speak the things which become sound doctrine,” he was telling him to speak to believers and tell them how to act in appropriate ways that make sound doctrine look good.
To do that, he tells aged men to be “sober” (2:2). The only thing sadder than a drunk is an old drunk, for hope that he will quit drinking has faded. “Sober” also means not thinking higher of yourself than you ought (Rom. 12:3), as aged men sometimes look back at their lives and do, like Nebuchadnezzar (Dn. 4:30). That’s not becoming to sound doctrine!
Aged men must also be “grave” (2:2), a word that means to be serious—serious about the things of the Lord! Sometimes aged men relax their commitment to the truth, thinking they’ve done enough for the truth in their lives. Knowing this, Paul tells them to be grave instead.
He also tells them to be “temperate” (2:2), which means moderate. It’s related to the word “temper,” which we think of as anger, but that’s what happens when you lose your temper. Your temper is the calm, moderate way you’re supposed to look at things without losing your temper. Not all aged men can look back at their lives and feel good about their accomplishments, and so get angry. But aged Christian men shouldn’t, because if you’re saved you’ve accomplished a praiseworthy amount of things for the Lord (I Cor. 4:5).
Aged men should also be “sound in faith” (2:2). “Sound” means healthy and strong (cf. Isa. 1:6). He’s not saying aged men should be strong in the faith, the body of truth given to Paul. That’s true, but here it means strong in faithfulness or dependability (cf. Rom. 3:3). Aged men need to be told to be sound in faith because with age comes weariness in well doing (Gal. 6:9).
Aged men must also be sound “in charity” (2:2), which means being sound in longsuffering (I Cor. 13:4), which gets harder as you get older! Charity also “envieth not” (13:4). Envy hurts worse when you get older because toward the end of your life you realize you probably aren’t going to ever get the things you spent your life envying!
Being sound in charity also means not being “puffed up” (13:4) with knowledge (I Cor. 8:4). Old men have to be warned about this because they have accumulated a lot of knowledge! Charity also doesn’t behave “unseemly” (13:5), or inappropriately in sensual areas (cf. Rom. 1:27). Being a dirty old man is unbecoming to sound doctrine.
Charity also “believeth all things” (13:7), that is, believes the best about someone. That’s hard for aged men after a lifetime of seeing people at their worst, but they must if they want to be sound “in charity.”
Aged men should also be sound “in patience” (2:2), a word often associated with being patient for the coming of the Lord (Ps. 37:7). That gets harder for older men after a lifetime of watching the unsaved prosper, as Psalm 37:7 talks about.
Are you sound in faith? One definition of “sound” is to strike something to see if it is strong based on the sound it makes when you strike it. If you’re not sure if you’re faithfulness is sound, you’ll find out when something in life strikes it. Similarly, if you’re not sure if you are sound in charity, you’ll find out when you offer someone charity and they lash out at you.
We should all learn to walk in ways that are becoming to the sound doctrine we preach. It’s not enough to believe sound doctrine, it’s not enough to teach sound doctrine. We must live sound doctrine in such a way that is becoming to it!