gambling is forbidden for the Bible, and as many religions say they are based on the Bible, then their subjects should not play poker ... but ... if you say it is an incomplete statistics game ... you have an excuse ...
I do believe poker is highly about statistics and risk management (as well as psychology and many other elements), but this isn't my "excuse"
Also, you didn't specify which religion, so I assuming it isn't Hinduism, or Taoism or something like that since you mention the Bible. Personally, I am a Christian. If what I say doesn't align with the Bible, then please correct me and I'll listen. With this said, I don't see where the Bible is against "gambling" inherently.
Here is my human opinion on it. Obviously, the Bible wouldn't mention "poker" by name because poker wasn't invented yet, but I see the problems not with poker (or even gambling), but with the way that people often approach these things; I argue that it is their flawed approach in mindset that is considered sinful in the Bible - not the game itself. Let me elaborate:
The Bible mentions in many places to put your trust in God and in many places it mentions the problems with temptation. It is really obvious to see how many poker players might be demonstrating their sinful nature because they play as get-rich-quick schemes, love of money and putting their lives to something else in an idol-istic manner.
One passage I am thinking of is the following, "But those who desire to be rich fall into temptation, into a snare, into many senseless and harmful desires that plunge people into ruin and destruction. For the love of money is the root of all kinds of evils. It is through this craving that some have wandered away from the faith and pierced themselves with many pangs." - 1 Timothy 6:9-10
Another passage that seems relevant comes from the book of Luke, "Then he said to them, 'Watch out! Be on your guard against all kinds of greed; life does not consist in an abundance of possessions.'" - Luke 12:15
Personally, I play poker because I enjoy psychology and the people-orientated game of poker is a great means to challenge this ability of mine. I like it as a game and for something to work harder to slowly improve at. With this said, sure I might consider playing for money if I become good enough (so far it is just
freerolls and homegames for me), but the temptation of getting rich isn't really in the forefront of my mind. Naturally, I wouldn't mind the extra money I may win (may lose money too; it is a game after all) - but this isn't the focus for me, nor does someone playing poker for money become inherently sinful in my eyes. I think the problem is if the person is controlled by this greed and love of money; I should note that many poker pros (religious or not) donate a lot of money for charity and give a lot of their winnings for other positive causes. Phil Hellmuth has donated a lot and so have other pros who have since become ambassadors for the game of poker. Obviously these professionals make a living at their talent, but it sounds like a strawman argument for some to claim that all poker players are drowning in greed (although sadly many players are - especially many recreational players).
Everyone is different, but when I was growing up: I never cared for poker. I knew the rules of the game (vaguely learned from a friend in elementary school one time), but poker was just another card game like go fish or crazy 8s (obviously we didn't gamble with money) and the game never interested me. I wasn't against poker from a moral standpoint, but it just didn't appeal to my interests and I didn't hold it against anyone who did play it. It wasn't until just a few months ago (I am in my 20s now), I literally woke up one morning and thought, "I
bet I could be good at poker"

Really that is how I started learning the game somewhat more formally and I've learned a lot. I like to think the psychology element is the strength of my game, but this meant nothing without the fundamentals and some basic math I am learning; poker can be a rewarding game - not just financially.
Anyway, this is my long-written opinion on the subject; I am open to hearing what others may contribute.
You know, a lot of televised poker events give the illusion that pots are many millions of dollars and high stakes pros are unimaginably rich; this couldn't be further from the truth in many cases. Why do you think so many pros go bankrupt - even multiple times! Yes, the pot you watched them play on tv may be several million dollars in size, but that isn't what the player is taking home that night. First of all, chip denominations are not always 1:1 on the currency. Also, even if it is - you can't always just get up and leave with your money. In a cash game you might be able to do so, but in MTT events on tv, they are usually only leaving when they win or when they bust (research ICM calculators to calculate how much each chip may be worth in
equity terms). Secondly, there is rake, taxes, money to pay others since many pros are staked for the money and so on.
Many pros have strong
bankroll management skills and slowly win more money little by little. Legendary poker pro Chris Ferguson says he doesn't usually like to spend anymore than 1% or his bankroll on any given event/night. This is smart because variance (due to the math underlining poker and its payout structures) is a very real thing and one can easily go bankrupt - so bankroll management is a net to make it more likely you can survive downswings. It isn't really a get-rich-quick scheme for many of these players who play professionally for a living.
I know I've got a long post here, but Proverbs is one of my favorite books of the Bible, so I have to end with a verse from here
"Dishonest money dwindles away, but whoever gathers money little by little makes it grow." - Proverbs 13:11
From my perspective, people who cheat to earn their money will have it dwindle, but long-term poker players usually have really good bankroll management and try to increase little by little - this can hardly be classified as falling into temptation and greed: which I think are the true sinful elements at play here, but this isn't limited to poker as a game though. It has to do with the mindset of the one playing poker and where they choose to place their values.