1. Followed by the Indicative Mood (with the Present Tense), it expresses the condition simply; without any reference to its being decisive by experience, or by the event, as in 1John 5:15, elsewhere, and in the Papyri.
   
   
2. Followed by the Subjunctive Mood, it expresses a hypothetical but possible condition, contingent on circumstances which the future will show (John 7:17).

1. Followed by the Indicative Mood, the hypothesis is assumed as an actual fact, the condition being unfulfilled, but no doubt being thrown upon the supposition (1Cor. 15:16).
   
   
2. Followed by the Optative Mood, it expresses an entire uncertainty; a mere assumption or conjecture of a supposed case (Acts 17:27.  1Pet. 3:14).
   
   
3. Followed by the Subjunctive Mood, like No. 1. b; except that this puts the condition with more certainty, and as being more dependent on the event (1Cor. 14:5).

John 13:17.  "If ye know these things (2. a, which I assume to be the fact) happy are ye if ye do them (1. b, a result which remains to be seen)".

Note four "ifs" in Colossian's, "if ye died with Christ" (2:20); and "if ye were raised with Christ" (3:1), both of which are No. 2 (assuming the fact to be true); "if any man have a quarrel" (3:13);  "if he come to you" (4:10), both of which are No. 1. b, being uncertainties.

One other "if" in Colossians is 1:23 :  "If ye continue in the faith" (eige = if indeed, a form of 2. a), which ye will assuredly do.