Many people usually only go in one direction in their interpretation with this as it seems at first that Paul is saying to Timothy to use a little wine as medical treatment for his stomach problems.
I speculate that Paul was telling Timothy to use less wine (a puny amount) as opposed to drinking too much of it because the excess wine Timothy was drinking was causing his stomach or esophagus problems (ulcers, heartburn?).
1 Timothy 5:23 KJV (23) Drink no longer water, but use a little wine
for thy stomach's sake and thine often infirmities.
We see earlier in 1st Timothy that Paul tells him to “take heed unto yourself”….that is, pay attention to your health and be persistent in doing things that support his own health. Healing will come if he was persistent.
Continue in them for in doing this you shall save ….that is, heal….yourself….and continue teaching so that those who hear will also be saved in the hearing of the Word of Truth.
1 Timothy 4:16 KJV (16) Take heed unto thyself, and unto the
doctrine; continue in them: for in doing this thou shalt both save
thyself, and them that hear thee.
As far as the water, I think Paul was telling Timothy to stop drinking a type of water. Maybe it was collected rain water that he was drinking instead of well water or it could have been water in a certain location that was making him sick.
Whatever kind of “rain” water he was drinking, he was instructed to stop drinking it entirely because it was also causing Timothy’s stomach/esophagus problems. Both the water and also the amount of wine he was drinking were causing Timothy health issues.
To summarize: Paul’s health instruction to Timothy required him to stop drinking (completely stop) the water he was drinking AND also decrease the wine he was drinking to a puny amount as both these things were causing Timothy health problems.
As far as the morality of drinking wine, the kingdom of God is not one based on eating and drinking but a kingdom of righteousness, and peace, and joy in the Holy Ghost. We must not judge another about what one eats or drinks. This is "stumbling".
Paul states that there is nothing unclean of itself….except if you consider it unclean then it is unclean to yourself and shouldn’t do it (because it is not of faith). Each person must be convinced in their own mind about these things.
If your brother thinks it is unclean, then we should not be drinking wine in front of him so that he might use his mouth to speak evil (stumble) in judgment of us. We must not cause our brothers to stumble by what we do in the brother’s presence.
Let us not judge another (judging = the “stumbling”) about what one eats or drinks….nor are we to put a stumbling block in a brother’s way by doing these things in front of him who does not believe in drinking wine (or else he uses his mouth to judge….evil speaking…. the stumbling).
Romans 14:13-17 KJV (13) Let us not therefore judge one another any
more: but judge this rather, that no man put a stumblingblock or an
occasion to fall in his brother's way. (14) I know, and am persuaded
by the Lord Jesus, that there is nothing unclean of itself: but to him
that esteemeth any thing to be unclean, to him it is unclean. (15)
But if thy brother be grieved with thy meat, now walkest thou not
charitably. Destroy not him with thy meat, for whom Christ died. (16)
Let not then your good be evil spoken of:
(17) For the kingdom of God is not meat and drink; but
righteousness, and peace, and joy in the Holy Ghost.
It is good not to drink wine….nor anything else…that might cause a brother to stumble or is offended because of it. Best to do it at home and not the offended brother's presence.
*Romans 14:21-23 KJV (21) It is good neither to eat flesh, nor to
drink wine, nor any thing whereby thy brother stumbleth, or is
offended, or is made weak.
(22) Hast thou faith? have it to thyself
before God. Happy is he that condemneth not himself in that thing
which he alloweth. (23) And he that doubteth is damned if he eat,
because he eateth not of faith: for whatsoever is not of faith is sin.*