user16667: Is there any authoritative sourced that a man can have more than one religion if he pleases?

user-1: Personal conclusion:: 
Dhamma gives me wings, free me from blind-faith, free me from sensual-pleasing-tradition-bounds, ... enable me to be more powerful. 
Religion whether it be Hinduism or buddhism or sikhism or christianism or jainism or muslim etc. binds me to blind-faith, binds me to sensual-pleasing-tradition-bounds,... makes me weak. 
To quest for authoritative sources 
All the suttas were composed 100s of years after buddha. So how much originality is still left, can't be claimed.  
Still, you may see this pre-sect-buddhism which is considered to be original teaching, still it is also considered to be mix of vedic, jain and sramanic schools of thoughts. 
Along with above, you might be interested in Mahayana, which in itself is a mixture of various thinkings, rituals, traditions, worships etc. 
To get to know how people, who call themselves to be on the path of dhamma, are engaged in various practices which can be easily found in other religions also which were either developed far from dhamma-touch or before buddha or after buddha can be seen here too. 
So now it's up to you whether you wish to remain within traps of religions or want to live freely under dhamma's guidance... 
Still, it's the practice and right understanding through which you will be able to claim dhamma. 
::::::::
To give a kick-start, you may go for Majjhima Nikaya. 
My ego-satisfying-view claims that Mulpariyaya, sabbasava, dhammadayada's 2nd half, bhaybhareva, Vattha, sallekha, sammaditthi, satipatthana, are as per dhamma. 
It is because my ego thinks that, "1st half of dhammadayada considers self-respect-issue(1 of the 8 worldly concerns), anangana lacks compassion, aankhankheya depicts somewhat maintain/gain-respect-issue. These might encourage some to practice more dedicatively but it will start with either greed or fear and work started for worldly concern is not a Noble path. 
:::::::: 

user471: Buddhism doesn't accept false views such as those listed in DN 1.
Many religions with soul and God reinforce the self view, the view of eternalism or other false views.
As such, it is not compatible to mix other religions with Buddhism, if they have false views according to DN 1.

user-1: It seems significant that HHDL advises us not to abandon the religion of our birth yet also encourages us to strive for realisation. This is the view that religion is a vehicle, not a destination. 
All those I know who endorse more than one religion also say, equivalently, that they have no religion. It depends whether we see our religion as a proscribed set of beliefs or a set of methods and practices for transcending belief. 
And then, talk to any three Christians and they will probably have three different religions, such is the game of Chinese Whispers. 

16667: <p>Is there any authoritative sourced that a man can have more than one religion if he pleases?</p>
 -1: <p><em>Personal conclusion</em>:: </p>

<p><strong>Dhamma</strong> gives me wings, free me from blind-faith, free me from sensual-pleasing-tradition-bounds, ... enable me to be <a href="https://buddhism.stackexchange.com/questions/36676/what-do-buddhists-think-of-the-premise-that-power-is-a-necessary-good-and-a-nece/36677#36677">more powerful</a>. </p>

<p><strong>Religion</strong> whether it be <em>Hinduism or buddhism or sikhism or christianism or jainism or muslim etc.</em> binds me to blind-faith, binds me to sensual-pleasing-tradition-bounds,... makes me weak. </p>

<p><strong>To quest for authoritative sources</strong> </p>

<p>All the suttas were composed 100s of years after buddha. So how much <em>originality</em> is still left, can't be claimed.  </p>

<p>Still, you may see this <a href="https://en.m.wikipedia.org/wiki/Pre-sectarian_Buddhism" rel="nofollow noreferrer">pre-sect-buddhism</a> which is considered to be original teaching, still it is also considered to be <em><code>mix of vedic, jain</code></em> and <a href="https://en.m.wikipedia.org/wiki/%C5%9Arama%E1%B9%87a" rel="nofollow noreferrer">sramanic schools of thoughts</a>. </p>

<p>Along with above, you might be interested in <a href="https://en.m.wikipedia.org/wiki/Mahayana" rel="nofollow noreferrer">Mahayana</a>, which in itself is a mixture of various thinkings, rituals, traditions, worships etc. </p>

<p>To get to know how people, who call themselves to be on the path of <strong>dhamma</strong>, are engaged in various practices which can be easily found in other <strong>religions</strong> also which were either developed far from <em>dhamma-touch</em> or before buddha or after buddha can be seen <a href="https://en.m.wikipedia.org/wiki/Schools_of_Buddhism" rel="nofollow noreferrer">here too</a>. </p>

<p><em>So now it's up to you whether you wish to remain within</em> <strong><em>traps</em></strong> <em>of religions or want to live</em> <strong><em><code>freely</code></em></strong> <em>under dhamma's guidance</em>... </p>

<p>Still, it's the practice and right understanding through which you will be able to claim dhamma. </p>

<p>::::::::<br>
To give a kick-start, you may go for <a href="https://www.accesstoinsight.org/tipitaka/mn/index.html" rel="nofollow noreferrer">Majjhima Nikaya</a>. </p>

<p>My ego-satisfying-view claims that Mulpariyaya, sabbasava, dhammadayada's 2nd half, bhaybhareva, Vattha, sallekha, sammaditthi, satipatthana, are as per <strong>dhamma</strong>. </p>

<p><code>It is because my</code> <strong><code>ego</code></strong> <code>thinks that</code>, "1st half of dhammadayada considers self-respect-issue(1 of the 8 <a href="https://taralanka.org/stuff/8-worldly-concerns/" rel="nofollow noreferrer">worldly concerns</a>), anangana lacks compassion, aankhankheya depicts somewhat maintain/gain-respect-issue. These might encourage some to practice more dedicatively but it will start with either greed or fear and work started for worldly concern is not a Noble path. </p>

<p>:::::::: </p>
 471: <p>Buddhism doesn't accept false views such as those listed in <a href="https://suttacentral.net/dn1/en/sujato#dn1:1.27.7" rel="nofollow noreferrer">DN 1</a>.</p>

<p>Many religions with soul and God reinforce the self view, the view of eternalism or other false views.</p>

<p>As such, it is not compatible to mix other religions with Buddhism, if they have false views according to DN 1.</p>
 -1: <p>It seems significant that HHDL advises us not to abandon the religion of our birth yet also encourages us to strive for realisation. This is the view that religion is a vehicle, not a destination. </p>

<p>All those I know who endorse more than one religion also say, equivalently, that they have no religion. It depends whether we see our religion as a proscribed set of beliefs or a set of methods and practices for transcending belief. </p>

<p>And then, talk to any three Christians and they will probably have three different religions, such is the game of Chinese Whispers. </p>
