Is it ok for Christians to engage in interfaith?

If by "interfaith" you mean things that contradict the Bible, then no.  Here is the truth: The Lord Jesus Christ is God. Nobody can be good enough to avoid hell. The truth is that death leads to immediate heaven or hell, depending only on whether the person believed on the Lord Jesus Christ, or not. The truth is that the Lord Jesus Christ loves you and wants to bless your life freely :) Most of all, Jesus wants you with Him forever, and not in hell. It is too late to be saved, after death.
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Believing on the Lord Jesus Christ means being forgiven all sins past and future and means going to heaven. The truth is that every belief except one will lead to eternal torment in the lake of fire for every person. Because nothing pays for our sins except the death and blood of Jesus, the sacrifice of Jesus that is already accomplished by Him . Jesus loves you! The truth is that the Lord Jesus Christ is God, and Jesus died on the cross to pay for all of our sins in full, and then Jesus was buried, and then Jesus resurrected from the dead. Nothing else pays for our sins, not works, not deeds, not religions. So the only way to heaven and to avoid hell, is by believing on Jesus for eternal life (John 6:47), without adding any of your own works (Romans 4:5). Believe in the Lord Jesus Christ to take you to heaven, and you will be in heaven, no matter what, guaranteed. That easy, thanks to Jesus! Tell Jesus that you thank Him that you will be with Him in heaven

For a person who is fully knowledgeable about the one true faith, and lives it fully, associating with those of other faiths poses no threat, and may provide the opportunity for those of other faiths to learn something about the true faith.

If by interfaith you mean to engage in religious activities of other religions, then No, because that would mean accepting other religions are as true as Christian faith - which is false.

However Christians can use Jesus' teaching to love their neighbors like themselves, but to not participate in their religious activities.

The local Catholic and Episcopalian church softball teams play each other if that is what you are referring to.

Matthew 4 satan showed Jesus the whole earth I will give this to you if you bow down to me  Jesus christ said Worship your God only 

If you stand up for the truth, fine. If you compromise the truth at all, it's not fine. There is only ONE way to heaven. The truth is that death leads to heaven or hell, and the only way to heaven is through faith in Jesus Christ.

The Bible is very clear that no one can earn their way to heaven since good works do not pay for sins. See Gal. 2:16, Rom. 3:23-28, 4:4-5, Eph. 2:8-9, Tit. 3:5. The only way to heaven is by believing in Jesus for His free gift of eternal life. Jesus shed His blood on the cross as the full payment for our sins. He did all the work; all He requires of us is that we believe in Him. Once you believe in Jesus Christ to save you, you are secure forever!

Because we have all sinned against a perfectly holy and righteous God, we all deserve eternal separation from God in hell (Rom. 6:23). However, God loves us so much that He sent His only Son Jesus to die on the cross as our Substitute so we don't have to go to hell. Christ died for our sins, was buried, and rose from the grave three days later (1 Cor. 15:3-4). He gives eternal life freely to anyone who simply believes in Him for it. No one can be saved by doing good works. Salvation is by grace alone through faith alone in Christ alone (Eph. 2:8-9).

"Verily, verily, I say unto you, He that believeth on me hath everlasting life" (John 6:47).

Interfaith = ecumenism = 263 heresies; each heresy leads to hell; Orthodoxy is the only true faith; most Orthodox priests are going to hell because "modern documents = heresy, ecumenism = heresy, electricity in church = heresy, kosher bread/wine = heresy, yeast bread/wine = heresy, etc."; falsely accused Patriarch Irenaios of Jerusalem (Theophilos 3rd is imposter) is the last Orthodox Patriarch; he blessed Catacomb movement (church in your house and not official building of heretics); forgive me. 

Why not? If even the thought of that makes you question your already fragile faith, don't do it. No sense destroying your world today, is there? 

THey would be considered arrogant and bigoted if they did not. 

OK, but dangerous, and I am talking denomonational, false faiths, NEVER.

Not every one that saith unto me, Lord, Lord, shall. enter into the kingdom of heaven; but he that doeth. the will of my Father which is in heaven Matt. 7:21.

You mean to "agree to disagree"?  As if that were a better choice than what you believe the truth to be?  Save that for politics!

Yes, it is perfectly okay. 
 
Here is the truth: Jesus Christ is nothing more than a limp and 
imperfect literary entity that has no control over anything more 
than the fact that Christians believe he exists.

When Christians finally learn to cast their religion aside, and
courageously come to understand that nothing will harm them
for having done so, then joyous, wonderful, and completely
healthy interfaith relationships will be able to flourish.