Appended text = to a string?

How do I check if a set of nodes appended together is equal to a string?

I know the following is wrong but it illustrates what I am trying to do:
<xsl:variable name="String1" select="<xsl:apply-templates select='text'/>"/>
<xsl:if test="$String1=$String2">
        Do something...
</xsl:if>

TIA
Linc