“Hold fast the form of sound words, which thou hast heard of me, in faith and love which is in Christ Jesus.”
2 Timothy 1:13

He says hold fast the sound words you hear in faith and in love. The Bible says:
“…Knowledge puffs up, but love builds up.” 1 Corinthians 8:1, ISV
You know, when you acquire new information, there is no guarantee that that information would change your life or elevate your estate, depending on how you received that information.
He tells in 1 Corinthians 8:1 that knowledge alone puffs up- and so people tend to judge or despise others:
“Why, then, do you criticize your brother? Or why do you despise your brother? For all of us will stand before the judgment seat of God… Therefore, let’s no longer criticize each other. Instead, make up your mind not to put a stumbling block or hindrance in the way of a brother.” Romans 14:10,13, ISV
Being puffed up is like a balloon receiving hot air- that isn’t real sustainable growth. It is love that builds, the knowledge you receive would cause beautiful changes in your life when received in love and not in a bid to prove a point or to argue, but to be inspired to walk in love towards others, even better than you did before.