Lets put that verse in context here, shall we.
2Ti 2:10 For this reason I endure all things for the sake of those who are chosen, so that they also may obtain the salvation which is in Christ Jesus and with it eternal glory.
2Ti 2:11 It is a trustworthy statement: For if we died with Him, we will also live with Him;
2Ti 2:12 If we endure, we will also reign with Him; If we deny Him, He also will deny us;
2Ti 2:13 If we are faithless, He remains faithful, for He cannot deny Himself.
2Ti 2:14 Remind them of these things, and solemnly charge them in the presence of God not to wrangle about words, which is useless and leads to the ruin of the hearers.
2Ti 2:15 Be diligent to present yourself approved to God as a workman who does not need to be ashamed, accurately handling the word of truth.
Being faithful to someone isn't the same as having faith in someone.
A woman or husband can be faithful to their spouse (that means they don't cheat on them) and yet at the same time not have trust in them.
As stated earlier. Jesus remains faithful to us when we fail. He won't turn his back on us. But notice in verse 12 what happens if we turn our back on him.
it's highly matter of interpreation on what paul is saying here.
"2Ti 2:12 If we suffer, we shall also reign with him: if we deny him, he also will deny us: "
can be taken as we must not deny our faith in Jesus or as we must not deny Jesus altogether (as savior).
the word Deny is greek word: arneomai which means:
Perhaps from G1 (as a negative particle) and the middle of G4483; to contradict, that is,
disavow, reject,
abnegate: -
deny,
refuse.
from these options the translators choose english word Deny. but this alone may give wrong idea from the original text. it could read "if we refuse Him".
not refusing Jesus as savior leads to suffering because you believe. the verse isnt talking about keeping the faith in my opinion, but accepting Jesus at first place or denying Him.
Being faithful to someone isn't the same as having faith in someone.
the word faithful is picked by translators from greek word pistos
which means:
From G3982; objectively trustworthy; subjectively trustful: - believe (-ing, -r), faithful (-ly), sure, true.
i agree there would be different word for believing in someone (that would be pisteuō (john 3:16)), than for faithful, like in this verse. But the point is that faithfulness , trusting God and generally believing seems to be covered by this word and lacking those attributes would therefore not be reason for God to deny you, according the verse. the point also remains
that God cannot deny him self.
and our lacking in faith doesnt give Him opportunity to deny us without denying Him self, because we never denied Him but believe in Him and have been born again into God's family.
issue is not do we believe God exists but that we have been saved by faith in Jesus.
and we are now His own. and our faithfulnes and trust toward savior from this point on isnt the issue, because of adoption that happened by realization of Jesus existence as our savior and accepting Him.
Also, it's not a good idea to build an entire theology on one verse, especially when the other side of the debate has given dozens of verses.
there are also dozen verses that support OSAS but are ignored. take john 3:16 for example. it says who believes will not perish but have everlasting life. Most people who say you can loose salvation seem to directly either lie against this or not remember the verse. because God's promise was who believes will be saved. so believing was only condition.
and most arguments always state you must do something else that just believe.